Fish Problems, when it goes wrong!

How to prevent tropical fish tank diseases

Fish disease is every aquarist’s nightmare. As always, prevention is better than cure.

A few simple precautions that could eradicate some fish diseases before they occur:

• Never introduce infected stock to your tank
• Don’t stress the fish out (i.e. by tapping on the glass)
• Don’t overcrowd the aquarium
• Don’t overfeed the fish
• Always keep the water in tip-top condition
• Always wash fresh greens (lettuce, cucumber) before feeding it to the fish
• Inspect your fish daily; are any looking a bit off?
• Never use chemicals, such as detergent to clean out the tank
• Always quarantine newly purchased stock – if this is not an option, simply drain the shop tank water away through a fine mesh fish net, and just add the fish to the tank.

However we strive to keep to the rules, diseases will happen. There are numerous fish diseases, some that we have heard of:

• White spot
• Cottonmouth
• Fin rot
• Scale rot

And some we may not have heard of, such as:

• Anchor worm
• Slime disease
• Black spot
• Gill flukes

Trying to diagnose the problem is the first step. Look at your fish and see if it has any outward signs of disease.

Does it have any spots?
What colour are they? – White spot? Black spot?
Are the fins looking raggedy? – Fin rot?
Do the eyes protrude? – Popeye?
Is it swimming on a tilt? – Bladder problem?

There are many drugs and treatments for fish diseases available on the market, including antibiotics, anti-fungals and antiseptics. Before we resort to these remedies, we can do a few home treatments.

Before anything else - Check the water

• Test the temperature – Is it too hot / cold?
• Test the pH – test for acidity/alkalinity
• Test for ammonia
• Test for nitrates

If any of the above are a problem, then this could be the cause of your worries. All tests are available to purchase from reputable fish specialists.

Caring for your sick fish
Diseased fish should be isolated, wherever possible.  This eliminates spreading the disease to the other healthy fish in the tank. Ideally a second ‘hospital’ tank should be set up, solely for the use of administering medications. The tank should not contain any ornamental decorations, gravel or plants; it must have adequate heating and a filtration system too.  Treatments should be administered as per the instructions on the box. Hospital tanks should be thoroughly sterilised after every disease treatment.

If you do not have a hospital tank, then a ‘salt’ bath should be administered. A salt bath is a good way of treating a fish, as salt is a good antiseptic and fungicide. Table salt may contain additives to stop it from clumping together, so it may harm the fish. We recommend that you use either rock salt, available from most supermarkets, or a specialist Aquarium salt. Give the fish a short bath in a bucket containing water and either salt, or the medication you have purchased.  Follow all instructions carefully.

Heat therapy can be used to kill some parasites. The temperature of the tank or bath should be raised gradually. Some parasites cannot tolerate higher temperatures and are killed. Aeration is a must in this treatment, as less oxygen is dissolved in warmer water. 

Keeping fish can be a worry for some, I can vouch of sitting worried about one that isn't performing as it should be, so when things go wrong and your fish seems to be having problems, what do you do?

Having kept fish for a few decades, we have stumbled across some commons problems within the fish we keep.