Frogs provide a fun alternative to fish in a nature pond

(Image by: belgianchocolate)

Over the past 100 years, pondlife has been in retreat as natural wetlands have been drained and old farm ponds filled in. One excellent way to help arrest the decline is to create a nature pond in your back garden.

Any body of water is a haven for wildlife, and you’ll be surprised just how popular your nature pond will become with the local plants and animals. Even if you live in a big city, you’ll soon find your pond is colonized by a wide-range of interesting flora and fauna.

Here are 10 tips on making the local wildlife feel at home.

1. Any sized pond will attract wildlife

If you’ve only got a small area that you can dedicate to a nature pond, don’t give up. Even a tiny pond made from waste liner offshoots or a dustbin lid will provide a natural water feature – and give some animals a home.

Position a small pond in partial shade, as otherwise algae can be a problem. Make sure the pond doesn’t dry out in summer, but in cold areas you’ll have to let it freeze in winter.

A larger pond of six-feet or more at its widest point will provide lots more ecological niches for wildlife. But a small pond is much better than no pond, so do the best you can.

2. Position your pond away from trees

If it’s to remain a pond not a muddy puddle, place your nature pond away from trees that shed leaves. Falling leaves can quickly silt up a pond, as well as providing too much shade and so stopping aquatic plants from growing.

The ideal nature pond gets a few hours of sunlight each day, to warm it up and power the photosynthesis of aquatic plants.

3. Provide hidden depths

Try to include both broad shallow areas and deeper water in your pond.

Shallow water will warm up quickly and encourage the growth of micro-algae and the tiny creatures that feed on it. Deeper water of at least 24″ in depth should stay liquid in winter. Such deep water gives pond wildlife a refuge in the coldest months.

4. Give your pond slopes and shelves

The ideal nature pond has some gentle sloping areas that run to the edge of the water. These slopes allow certain animals to access the pond, but more importantly they provide a way for others to get out. Hedgehogs, for instance, will drown in a pond they can’t scramble out of.

Shelves positioned 6-12″ below the water surface can support baskets of marginals, rushes and other plants. Waterlilies and oxygenating plants are best planted in baskets in the deeper areas.

5. Use a modern pond liner

It’s possible to build a pond by ‘puddling’ clay, but I can tell you from experience it’s not easy to keep one. Farm ponds relied on the trampling of sheep and cows to stop them cracking – not something your cat or dog is likely to do for you in your back yard!

It’s much easier to build your pond using a modern liner such as butyl, which can be shaped and folded to provide exactly the pond you require. Installed properly, such liners last decades.

6. A small pump won’t hurt your natural pond

You don’t want a fountain shaped like a mermaid in your nature pond, but a small pump is a good addition.

Gentle water movement will increase the gas exchange and improve circulation in your pond. You may even want to create a small stream or mini-waterfall.

A solar powered pump is a nice compromise, keeping your nature pond ‘off-grid’. Consider removing the pump in winter, to enable the water to naturally settle into temperature zones that wildlife can use as best suits them.

7. Plant the margins as well as the pond

Don’t just think about pond plants. The best nature ponds have only vague boundaries, as the marginal planting at the edges gives way to hostas and rushes, which in turn bleed into the garden borders.

Such planting provides a safe way for wildlife to move unmolested by predators such as cats and birds. It also looks more natural.

8. What about a bog garden?

While you’re thinking about near-pond planting, consider creating a bog garden. A bog garden is simply a wetter area of ground near the pond, which you can create by burying a piece of pond liner in such a way as to stop some but not all of the water seeping away.

Some pond experts suggest you have the lip of your pond spill over into your bog garden, so that after heavy rain the water runs over the pond edge and into the bog garden. I don’t suggest that though, since you’re just as likely to find mud and detritus running back into your pond.

To really make wildlife feel at home in your bog garden, pile up some logs or rocks to give animals such as toads and newts a place to shelter when they’re not in your pond.

9. No fish – except tiny natives

Ever fed small live food such as daphnia to your tropical fish tank? Did any of the tiny creatures last more than two minutes before being snapped up? Thought not!

Fish are voracious predators, and it doesn’t take many to denude a pond of natural life. I’d keep fish out of any pond less than six-foot in width or length.

If your pond is bigger than that, a few small fish such as sticklebacks won’t hurt. It’s very entertaining to watch them build nests in the shallows, and to hover in the water as they hunt their prey.

10. Keep it clean

So your natural pond is built and planted up, your marginals are blooming, and animals have started mysteriously arriving to live in your pond.

Job done? Not quite.

Even a nature pond will benefit from a helping hand. True natural ponds come and go as pools are formed and silt up over time. Presuming you want to keep your pond for years to come, I’d suggest you:

• Clear marginal planting as it begins to die back
• Give the pond a dredge with a net to remove leaves and gunk
• Net floating leaves before they sink in autumn

Carefully inspect anything you take from your pond to make sure you’re not throwing away the wildlife you’ve worked hard to attract!

One idea is to pile the waste by the pond edge for a few days before composting. This way, smaller animals such as dragonfly larvae, newts and snails have a chance to crawl back into the water.

Bonus tip: Let your pond life come naturally

Do the planting yourself in spring, but let animals find your pond naturally.

Dragonfly seem to have a radar for water, and will often be spotted within 24 hours. It might be a year or two before you see any frogs or newts but come they will, especially if your pond is near to another natural body of water in a local park or preserve.

Note that it’s illegal to disturb many threatened native species. In the UK, you can only move Great-Crested Newts with a licence, for example.

If you find protected animals in your pond, prepare to be a nature warden as well as a pond owner!

Further reading:

1. A lovely lost nature aquarium blog
2. Coral reefs recover from 2004 tsunami
3. More dead zones in the ocean discovered

Fin rot is treatable without a stake through the heart, however, by improving tank conditions and using one of several different treatments as discussed below.

Symptoms of fin rot

Fin rot is fairly easy to diagnose, though ideally you want to catch it when the disease has barely progressed as it will be much easier to treat.

• The first signs of the disease are milky white areas appearing in the fish’s fins or tail, particularly around the edges.
• The fins develop a rather ragged appearance as the disease begins to eat the tissue.
• Eventually the disease eats all the clear fin membrane away, leaving just the fin rays.
• If the fin rot has affected the fish’s tail (also called tail rot), it may work its way through to the body of the fish.
• Secondary infections or diseases are common in advanced cases of fin rot, bringing new symptoms to the afflicted fish such as white cotton wool-like tufts or streaked patches of red.

If you catch fin rot early you can treat the root causes and let the fish take care of itself, which is always better than treating the whole aquarium.

Make sure you don’t misdiagnose a fish that just happens to have been bred to have frayed fins. Also, fin-nipping can cause a fin rot-like appearance in fish like guppies.

Causes of fin rot

Fin rot is a bacterial infection. It’s likely that several different bacteria cause similar diseases, with Flavobacterium columnare (previously known as Flexibacter) most often blamed. Aeromonas and Pseudomonas are also cited.

However it’s not really right to say the bacteria cause fin rot. Almost always fin rot only occurs in weakened fish, most often because of poor tank or pond conditions. Physical damage or an attack by parasites can also leave a fish susceptible to fin rot.

Fin rot often only manifests itself in one or two fish at once and it is not particularly contagious, adding more weight to the theory that a weakened immune system is required for the disease to take hold.

Treating fin rot

There are three ways to treat fin rot:

• Environmental
• Anti-bacterial treatment
• Antibiotics

Fixing the environment

Fixing the environment is the most important element by far, since if the tank is in a bad way the fish will become reinfected with fin rot in the future, not to mention other inhabitants getting the same or other diseases. Fin rot is a wake-up call that you need to sort your tank out.

Do a couple of large 20-50% water changes with clean, aged water, and try to suck up as much debris and detritus as you can. Check and clean all your filters. Give the gravel a good clean, especially if you’re using an undergravel filter.

Look out for any tank bullies that are nipping or fighting with the other fish, and either remove them or the other fish. Similarly, if your tank is over-crowded you’ll need to remove some of its inhabitants to a new home.

Using an anti-bacterial treatment

Various anti-bacterial treatments and fin rot cures are effective against fin rot if caught early enough, such as Melafix (US link).

Treatments designed for aquariums or ponds should be safe if used according the instructions. If you can though, move the afflicted fish to a clean aquarium with a simple filter for treatment, rather than treating the whole tank. (Proper anti-bacterial fish medicines should not affect ‘good’ filter bacteria if applied in a proper dosage).

Treating with antibiotics

In the US it’s common to treat fish diseases with off-the-shelf antibiotics. Ask for a treatment that’s effective against gram negative organisms – there are several, which are sold under different names.

In the UK and other countries which have a more sensible attitude towards mankind’s best defense against diseases, antibiotics are typically only obtainable under guidance from a vet. As such, they’ll only be cost-effective with expensive fish, such as large koi or marine fish. Ask your vet.

Catch fin rot early enough and you shouldn’t need antibiotics anyway; better for you, the fish, and the world.

Preventing fin rot

Fin rot can usually be prevented by keeping your aquarium or pond in good condition, as discussed.

Set your tank up properly. Once running, check your tank or pond is sensibly stocked, and make sure you’re doing regular water changes (at least 25% a month, and ideally 10-20% a week). Consider whether you need to choose a new filter if your fish a messy eaters or you’re struggling to keep the tank clean.

Finally, diet has a crucial role to play in keeping fish fit and healthy. Make sure you’re feeding a wide variety of fresh foods, and that all the fish are getting enough to eat.

Further reading:

1. Floating goldfish: Causes and cures
2. 7 beginner’s tips for buying healthy fish
3. Curing seahorses of gas problems

Don't crowd your aquarium, it can only hold so many fish

There are guidelines about how many fish you can keep in an aquarium, but few experts would claim they are scientifically exact. The two main rules of thumb on stocking an aquarium are based respectively on the surface area of the tank (which influences oxygen levels) and the tank volume (this takes pollution as well as oxygen into account).

Many other things can alter how many fish an aquarium can healthily support, including:

• The shape of the aquarium
• The filtration system employed
• Surface agitation
• Water temperature
• Tank maintenance regime
• The kinds of fish being kept

Note: You can’t stock to the maximum capacity on first setting up! If your tank can hold, say, 20 small tropical fish, you should build up to that over a period of 3-6 months, to give the tank a chance to mature without a dangerous spike in pollutants.

With those caveats in place, let’s consider the common guidelines.

Fish cm per liter / fish inches per gallon

This was the rule I was taught when I first started keeping fish, and it’s still the most common stocking guide today.

1. Calculate the volume of your aquarium in liters or gallons
2. Work out the length of your chosen fish from nose to base of the tail
3. Consult the table below

Kind of fish       Inches / gallon     cm / liter
Coldwater            1" / gallon          2.5cm / 4.55 liters
Tropical             1" / 0.5 gallon      2.5cm / 2.25 liters
Marine (reef)        1" / 4 gallon        2.5cm / 18 liters
Marine (Fish-only)   1" / 2 gallons       5cm / 9 liters

For example, a 30-gallon aquarium could hold 30″ of coldwater fish, 60″ of tropical fish, or 15″ of marine fish.

Important: I am using Imperial (UK) gallons here. To work out US gallons, multiply UK gallons by 0.83 (or just stick to liters!)

The advantages of the fish inches per gallon rule are that it is easy to understand, since most people know their tank’s volume, and it takes into account the total volume of the tank. “The solution to pollution is dilution” is an old fishkeeping phrase. Bigger volumes of water can obviously carry more fish waste such as nitrate before there’s a problem.

The disadvantage of the rule is it does not take into account the tank shape. A tall, thin tank of 40-gallons will, according to this rule, have the same carrying capacity as a shallower, longer tank. But in reality the shallow tank will offer a much bigger surface area for gas exchange. In filter-less tanks particularly, it makes a big difference.

Fish length per unit of surface area

This rule puts aquarium surface area to the fore:

1. Calculate the surface area of the tank in square inches or centimeters
2. Work out the length of your chosen fish from nose to base of the tail
3. Consult the table below

Kind of fish    Inches / sq inches      cm / sq cm
Coldwater         1" / 30 sq inches        2.5cm / 190 sq cm
Tropical          1" / 12 sq inches        2.5cm / 75 sq cm
Marine            1" / 48 sq inches        2.5cm / 300 sq cm

A 36-inch long by 12-inch wide tank will therefore hold 14″ of coldwater fish, 36″ of tropical fish or 9″ of marine fish.

The advantage of using the surface area guideline is that it takes oxygen exchange directly into account. The ‘per gallon’ rule also does (that’s why coldwater fish need more gallons than tropicals) but not so directly.

The disadvantage of the rule is that people aren’t so aware of their tank’s surface area. It’s easy to work out: just multiply the width of the tank by the length. But it’s harder to keep in mind when you’re in the aquarium store wondering if you can add a few more fish.

Other issues with stocking levels

This article could run forever, so I’ll just add a few more caveats and pointers you should take into account.

Water displacement because of decoration means your tank won’t hold as much as its theoretical volume. Take off at least 10% to account for gravel, rocks, lots of bogwood and so on. With a very heavily furnished tank, take off 15%.

Different fish need a different amounts of space. Active fish like tangs or danios require more swimming room then relatively static fish like clownfish or neon tetras. Many fish require a certain-sized territory. For instance, I’d only keep one pair of dwarf cichlids in a two-foot freshwater aquarium. These measures have nothing to do with theoretical volume.

Big fish need more room than the equivalent number of little fish. Two six-inch long catfish will require a much bigger tank than 12 one-inch tetras. Their biological load is greater, and they’re messier eaters.

You can generally ignore shrimps, snails, plants and inverts when making your calculations, as they have a small biological load and often contribute to the tank’s carrying capacity (such as plants which oxygenate by day or critters that clean up detritus). Two caveats: In large numbers they will make a difference (such as a snail infestation in a tropical tank), and marine inverts can be more sensitive to poorer water quality (hence the lower stocking suggestion per gallon above).

Strong water circulation, big filters, airstones and so on can increase the stocking level of your aquarium, but I wouldn’t recommend it. Better to have healthy fish with enough room to roam unmolested than to cram in another fish or two and risk disease and infighting.

Remember, these are just rules of thumb. Erring on the side of caution is always the best policy with aquariums, and an under-stocked tank is far easier to keep in good condition than even a slightly over-stocked one.

Further reading:

1. Choosing filters for fish tanks
2. Video guide to setting up your first tropical fish tank
3. Coldwater marine tank in Norway

If you have any more tips to add after reading, please drop us a line in the comments below!

1. Use plants instead of a filter

Setting up a new tank to grow plants? If you’re already spending money on decent lighting and a good quality substrate to help ensure your plants thrive, you may be able to save money by skipping the filter.

On her excellent natural aquariums website, Rhonda Wilson explains how she uses plants to keep her tropical tanks naturally sweet:

There are several reasons why I enjoy natural aquariums as opposed to those that are mechanically filtered. I find the equipment to often be distracting from the beauty of the tank. I’m interested in the interaction of different factors that make up a living system.

I know some people really like to play with all the aquarium equipment and that’s OK if you like to collect equipment. I prefer collecting different types of plants, fish and invertebrates to go in my tanks.

Here’s one of her articles explaining how to set-up a natural aquarium.

2. Use rabbit or guinea pig droppings as plant fertiliser

Filled your tank with plants but worried about the cost of expensive German fertilizers? Some plant enthusiasts swear by using rabbit or guinea pig droppings as targetted fertiliser tablets.

Dry them out in the sun, and then bury a couple in the substrate near big specimen plants like Amazon Swords and Cryptocyrenes. Go slow at first, and don’t overdo it.

Don’t use any other animal waste as it won’t be appropriately constituted and could pollute your tank.

3. Build your own DIY stand

Most aquarium stands are absurdly expensive for what they are – four or five pieces of machine cut, man-made wood, stuck together with screws

If you’re at all handy, there are loads of guides on the Internet on how to build your own stand. Here’s a few to get you started:

• A DIY stand plan generator to suit any tank size
• A guide to making joints to support the weight of a fishtank
• Plans for a heavy-duty stand you can scale to your needs – it looks like it could hold up a house!
• Here’s a 4-foot aquarium cabinet step-by-step guide

4. Get your fish for free

Ever moved house and had to give your fish away for free? I’ve done this more than once, and I know others have as well.

Generally you’re forced to push your homeless fish onto aquarium-owning friends, or even return them to a shop who reluctantly takes them off your hands then sells them the next day. (A man’s got to make a profit, I suppose.)

This is the age of the Internet, however, and there are countless opportunities for you to advertise your need for particular free fish in your local geographical area. Craigslist and Gumtree are two ad services, or you could simply post your requirements in an aquarium forum.

If you’re after livebearers you will be inundated with offers. I bought three supposedly female platies last summer. I now have about 20 platies in one of my tanks, and they’re still breeding. I can’t give them away fast enough!

5. Turn down the temperature

Many tropical freshwater fish are quite happy at temperatures of 21°C / 75 degrees Fahrenheit, yet are kept at 26°C or higher. A few do require higher temperatures, most notably discus and some South American tetras, so be careful.

If you check the lower safe range of the fish you keep, you may find you can bring the temperature down by a few degrees, which may stop the heater going on at all for most of the year in a centrally-heated house.

A few fish kept as tropicals, such as White Cloud Mountain Minnows, actually prefer no heater at all – an indoor unheated tank will suit them fine, which will save you buying a filter. And coldwater fish like goldfish certainly shouldn’t be kept in heated tanks (but people do).

Got a reef tank? The blog glassbox-design posted some tips on cutting costs earlier this week.

Further reading:

1. Five ways to turn your iPhone into an aquarium
2. Soil as a substrate in the planted aquarium
3. Algae control in a freshwater aquarium

Goldfish suffer more than their fair share of gruesome ailments, of which floating listlessly at the surface is a common one.

Floating doesn’t seem to happen much with tropical fish, yet you can barely walk past a typical pet shop’s bank of coldwater tanks without seeing at least one goldfish bobbing about at the surface, or even lolling upside down.

The good news is the floating often corrects itself after a few days, and it’s rarely contagious. The bad news is affecting a cure to permanent buoyancy problems can be impossible.

What causes goldfish to float?

Invariably the cause is a swimbladder problem in the affected goldfish. This often manifests itself in floating behaviour, although it can also be seen in fish that sink to the bottom of the tank. In both cases the fish is unable to use its swim ladder to maintain the proper position in the water.

There are many causes of swimbladder problems, and most are difficult to consistently treat, in part because it’s difficult to tell exactly what’s wrong with your fish.

Common causes of swimbladder problems include:

• Intake of excessive air when eating from the surface
• Build-up of gas within the swim bladder
• Bacterial infection leading to an accumulation of fluid in the swimbladder
• Physical damage
• Incorrect internal growth, or even a tumour

Treating floating goldfish

If the fish doesn’t right itself after a few days then there are a few different treatments you can try. Unfortunately none of them is guaranteed to work.

Starvation or an exclusive vegetable diet

Stop feeding the fish and see if it’s able to expel the gas over a few quiet days. Alternatively, try feeding only crushed fresh peas. Sometimes this helps the fish to purge its insides of excess gas.

Increasing the water temperature

Raising the tank temperate by a few degrees (to a maximum of about 24 degrees Centigrade) can help a fish rid itself of excess gas. Like the starvation cure, it won’t work if there’s a more serious physical problem with the swimbladder.

Try adding some salt to the water

An old-timers cure is to add salt to the water. Sodium chloride, sold as tonic salts in fish shops, can occasionally work a miracle cure with goldfish (be careful with other species of fish in the tank that may not be able to tolerate salt in the water). Add a couple of grams per litre to the tank, or else treat the affected fish with a prolonged bath. Always follow the instructions on the tonic salt packaging.

You could try an anti-bacterial remedy

Several anti-bacterial medications are available. In my experience they seldom do much with serious buoyancy problems, but provided the instructions are followed carefully, it won’t hurt more than your wallet to try.

If your fish doesn’t respond to treatment, you may need to consider putting it to sleep, particularly if it’s suffering distress.

Buoyancy problems seldom affect more than one goldfish at a time, so if the problem recurs look for underlying problems with your aquarium. You might try to ensure dried foods are sinking quickly to avoid excessive air intake at the surface.

Making sure the tank is adequately filtered and doing regular water changes will go a long way to preventing any problems in your fish tank.

Further reading:

1. Chinese selling live goldfish in keyrings as Olympic souvenirs
2. Curing seahorses of gas problems
3. Fin rot: Symptoms and treatment