Everyone who keeps ornamental fish wants them to be healthy, and it’s not that difficult to achieve.Yet the whole area of fish health carries with it a certain amount of fear. People are scared that their fish will die and that the time, effort and money they’ve invested in an aquarium or pond will be wasted. But really, all you have to do is understand a few basics to achieve success with your fish.
Look after the fish tank water
The first basic to grasp is that fish kept in good conditions with minimal stress rarely get sick in the first place. Look after the water and the water will look after your fish. Do the basics well and do them often. Carry out lots of partial water changes, service filters regularly, check the temperature of the aquarium daily, for tropical fish anyway, and get the water tested regularly. The exact tests required and water quality you want to maintain will vary depending on what fish you are keeping but the vast majority of community aquaria ( 90% of them) should be 25ºC with a pH of 7 to 7.5.
Feeding your pet fish
The second basic has to do with feeding. You often hear about the dangers of overfeeding ornamental fish. Overfeeding is certainly a common problem, but be aware: overfeeding refers not to the fish eating too much, but rather to leftover food, which will decompose and pollute the aquarium. This misconception has led to fish ending up poorly nourished as their owners are afraid to feed them. Fish need to be fed little and often, at least twice a day, and more often would be better. One of the few exceptions is for garden ponds that are lightly stocked with fish. Here, there will usually be sufficient food naturally and anything supplied by the owner is supplementary.
Fish should also be fed a variety of food. You can keep fish alive using only flake food, but fish fed a variety of foods, including frozen and live food, will be healthier, live longer and be more colourful. Don’t forget that some fish are specialist feeders, too. Some, such as catfish and loaches, feed off the bottom and others, including suckermouth fish, are largely herbivorous. Therefore, appropriate foods need to be supplied. It is very common to see skinny and half-starved fish of these types, even in some pet stores, regrettably.
Not all fish go well with each other!
Basic number three is to consider tank mates carefully, as not all fish live together happily. Some will simply eat others and, as a general rule, if a fish can swallow another one whole it probably will. More commonly though, health problems arise as a result of vigorous ‘fin nipping’ or territorial fish being kept with more placid tank mates. Typically, the more placid species will hide a lot, feed poorly and either succumb to disease or simply waste away.
Introducing new fish to your aquarium
It is essential to always introduce new fish to an aquarium gradually. One of the greatest stresses, and therefore precursors of disease, for a fish is being netted, bagged, transported and placed in a new tank. Always float the bag containing new fish in your aquarium for 15 minutes to allow water temperatures to equalize, then add some tank water to the bag and leave another 15 minutes. Then add more tank water and leave again. Finally, net the new fish out of the bag and place it in the aquarium, then dispose of the bag water. Don’t add it to your aquarium.
What to do if your fish get sick
Right, so you have done all the basics well and still your fish get sick. What do you do? The main thing is to act quickly, as tomorrow or ‘in the weekend’ may be too late. First, seek good advice, which usually means a good aquarium store as, regrettably, few vets in New Zealand know much about fish. Make sure you have a good description of the symptoms and advise accordingly and if your fish has a disease, will offer a cure. Special note: if using aquarium medications, first remove any carbon that may be in your filter as it will filter out the medication!
Having covered most of the ways to avoid disease, here’s a brief description of the common diseases and other health-related symptoms that fish may exhibit.
Whitespot disease on your fish
This is the most common fish disease and, as the name suggests, the main symptom is white spots on the skin – almost as if the fish has been sprinkled with salt. The spots are actually cysts where the whitespot parasite lives. A cure will take at least several days but there are a number of very effective treatments on the market. Whitespot often occurs after a chill so check your heaters are working properly.
Fungus infections on your fish
Fungus looks like growths of white cotton wool on the fish. Fungus is a secondary infection and often grows on wounds or other areas of infection. You can purchase treatment for this problem over the counter and some antibiotics will also be effective, but these are only available from your veterinarian. Often described as ‘mouth fungus’ is a bacterial infection called Columnaris. It looks like white fungus around the mouth but is actually a secondary infection, and no amount of treatment for fungus will cure this complaint. Instead, you will need to purchase treatment specifically formulated for Columnaris.
My fish is scratching itself?
‘Flicking’ is the term used to describe a fish scratching itself repeatedly against gravel, plants or aquarium decorations. It can indicate whitespot or it can be a sign of ammonia in the water.
My fish are gasping at the surface. Is this a problem?
‘Gasping’ is when a fish consistently mouths at the water’s surface. This may mean low oxygen levels in the water and is often the result of too high a temperature – warm water naturally holds less oxygen. Gasping can also indicate ammonia in the water, which inhibits the fish’s ability to utilise oxygen.
There are many other fish disorders, and if you really want to know more about them, have a look at the numerous books available on the topic. And, of course, there is also the internet. I always believe that for fish keepers prevention is far better than cure.