Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Fish keepings hall of shame



This is a personal view about all the things which I find distasteful about fish keeping. The vast majority of fish keepers want to do the best for their pets and most spend an awful lot of money in doing just that. But there are those who simply want to make money out of the hobby which in itself is fine but there are a few who will stop at nothing to maximise their profits even at the expense of the fish they are making those profits out of.

Genetically modified fish

Glo fish: Originally the first fish to be genetically modified were created in the name of science. Their colour indicated whether there was any pollution in their water. How you feel about this is down to personal choice but at least there was a genuine and valid reason for creating them. Since then many more species of the so called glo fish have been created.

glo fishPhoto source

Then they became available to hobbyists as a novelty item, they were supposed to be sterile in order to prevent them from harming the environment should any be released either accidentally or on purpose. Some hobbyist have managed to breed them!!! and then it came to light that the company selling them had a patent on them preventing anyone else from producing them, highlighting that to them the fish are little more than a monopoly to make money. Do we really want a situation where we are forced to buy our fish from a single supplier with a patent and we be denied the joy of breeding our own fish?

It seems a high price to pay for a novelty fish which glows under certain lighting.

Parrotfish: Parrotfish are thought to be hybrids which have been artificially created because the original parent fish seem unlikely to breed naturally but this is speculation because those details have never been released.

Parrotfish are unable to fully close their mouths and this must interfere with both respiration and feeding. They have either very low fertility or they are in the majority of cases sterile. This again is to protect the producers financial interests in these fish. Even so the fish when well cared for will regularly go through the motions of breeding in typical cichlid fashion. The very few which have managed to breed successfully in captivity have produced unattractive olive green young only.


As if being deformed and dyed wasn't bad enough some of these fish are selected to become "Heart" Parrotfish, to achieve this they have their tails cut off with scissors at the point where the tail joins the body in order to prevent regrowth. No anesthetic is used and the resulting wound is simply left to heal. Others have messages tattooed on to them by laser. It seems a lot for a fish to go through just for novelty value. Would any serious fish keeper want these when the facts are known?

Dyed fish

Dyeing was one of the very first methods used to abuse aquarium fish in an attempt to make more money from them. Dyed fish have been around since about the mid 1990's but little research has been carried out in to the long term effects of the dyeing process has on fish. One thing is for certain - no fish having been dyed benefits in any way from the process. Anecdotal evidence suggests that mortality is increased, incidence of disease is increased and life is shortened. A 1998 survey carried out in the South of England revealed that over 40% of painted glassfish showed signs of a Lymphocystis infection, compared to 10% of unpainted glassfish .This should put people off buying the fish but sadly a lot of new fish keepers are mislead about the process with lines like.

dyed fish
dyed fish

diseased dyed fishdyed and diseased fish

Above are two dyed fish showing symptoms of disease

"They are fed a special colour food at the breeders"

"They are specially bred with those colours"

Some dealers will flatly deny that the fish have been injected with a dye to produce the lurid fluorescent colours but sadly that is exactly what has happened. Practical fishkeeping magazine have run a long standing campaign against these fish and a lot of shops signed up and pledged not to sell dyed fish but in reality the fish are good sellers and I have visited several shops who signed up but still had dyed fish on sale.

Methods of dyeing

Fish are injected with dye, the same needle will be used to inject many fish, in all likelihood it will be used until it becomes to blunt to carry on. The size of the needle compared to the size of the fish means that there is likely to be significant tissue damage at the injection site. Again it is difficult to be precise because the process is closely guarded for obvious reasons. Using the same needle for a large number of fish also greatly increases the risk of disease transmission along with the stress caused there will be increased mortality but the extra sales generated make up for this.

Dipping, this involves the fish being dipped in a caustic solution which removes the fishes mucus coat (which is the fishes first line of defence against infection). The fish is then in a solution with the dye and finally it is placed in a solution which contains an irritant which causes the fish to regenerate its mucus coat.

Laser, work by Lee Blankenship and Dan Thompson of Washington Department of Fisheries in 1993 investigated the use of Coumarin Dye (CD) lasers. Blasts from the lasers tore away scales and the epidermis down to the surface of a layer of tissue called the stratum compactum this removes any of the fishes original pigmentation and allows the new colour to be applied. Using this technique which is very precise actual words or patterns can be written on a suitably sized fish leading to things like "I love you" being written on fish around valentine's day.

If the fish survives these processes you will still have ended up wasting your money because the dye used isn't permanent and usually fades after several months.

Fancy goldfish

From the start I have to admit that I like fancy goldfish, they have a long history in fish keeping and it could be argued that they actually began fish keeping as a hobby hundreds of years ago.

But!!! I am very uncomfortable about some of the fancy goldfish varieties which are well established in the hobby. In particular the two which I have the most concerns over are:

  • The Celestial, which has eyes which bulge from their sockets and point upwards all the time.
  • The bubble eye, which has a fluid filled sac below each eye, these sacs are easily damaged and in my own view based on observation alone they interfere with normal day to day behaviour of the fish and leave them at a huge competitive disadvantage. If you do keep bubble eyed goldfish it is probably best to keep them well away from sharp or abrasive substrates and other objects in their tank which might have the potential to cause injury to the sacs. They should also be kept with just their own kind.

dyed fish
dyed fish

Bubble eyed goldfish
Bubble eyed goldfish

The Celestial goldfish
The Celestial goldfish

Both these varieties seem to impinge to much on the fishes daily lives and as such seem a  step to far in my own view.

Tank busters

Juvenile red tailed catfish
Babies like this soon grow up

Baby red tailed catfish, shovel nosed catfish and their hybrids sell at a very fast rate when offered for sale as babies like in the photo above. But they grow very quickly and their growth isn't restricted by their tank size as a popular fish keeping myth suggests. But what happens to these fish? Public aquariums no longer take them, pet stores don't normally have the facilities for very large fish and realising that they would be stuck with such a fish they are generally unwilling to take them anyway.

Releasing them in to the wild does happen but these fish are tropical and won't survive a British winter even in milder parts of the Country. What ever the fate for the growing fish there are far fewer adults around than there are young fish sold which means that the majority are dying prematurely.

Whilst there is nothing wrong with large fish and I wouldn't like to see legislation preventing their sale it is the people who have inflated ideas about their fish keeping ability where the problem really lies. Do your research (other than just asking the vendor) and be honest with yourself about whether you are able to maintain a particular fish for its entire life.

Novelty aquariums

Tiny tanks, small sealed bowls embedded into handbags, tiny (permanently) sealed bags attached to key rings, the list is long and growing.

Tiny novelty aquarium
No comment needed

None of these things make suitable homes for fish and what is worse they reduce the status of a living creature to that of a novelty item. Death is guaranteed and in some cases possibly welcome.  The sealed containers often contain an harmless dye which vendors often claim to be some sort of nutrient, this is of course utter rubbish and the fish is doomed to suffocate long before it starves.

As an experienced hobbyist I would consider a 60 litre aquarium as the smallest which should be used for housing fish on a permanent basis although for some applications like maintaining a trio of small killifish for breeding an exception could be argued for and a tank of around 12 litres (12" x 8" x 8") again this has no scientific basis and is simply a personal view.


Hybrid: The young whose parents are from different species

Genetically modified: Is when the DNA of a species is artificially altered on purpose in order to make a modification.


WikipediA - Glo fish
WikipediA - painted fish