please help, my fish are dying

Question
please help. ive noticed today that all 4 of my fish are staying at the bottom of the tank, floating very strangly hitting the bottom of the tank. also i have noticed that they are swimming upsidedown and on there sides, i have to keep gently poking them to see if they are still alive. i think it was on monday that i did a complete water change as the water was abit green, after that they seemed fine. yesterday i cahanged the sponge in the filter as i had heard they are supposed to be changed every so often.today is when i noticed that the fish are not there normal selves. i have had the water tested which has come back fine, and this evening have also added tap safe to the tank but still no change.i really dont know what to do. am so worried they will have died by the morning. a pet shop said they could have swim bladder, really not sure what that is, and how would that come on over night. please help, many thanks kate

Answer
Hi Kate,

I'm assuming that these are Goldfish that you are talking about. To be more precise probably Fancy Goldfish. The problem with FG's is that they have been captive bred to look they way they do. Line breeding gives them their distinct shape and finnage. Although they look prettier than their 'common' cousins; they aren't as sturdy and the swim-bladder has split in two. Strong currents, temperature fluctuations and rapid change in water parameters can all affect the swim-bladder.

However, FG's are also prone to constipation. The digestive tract is delicate and short, they don't have a stomach and flake food has a habit of swelling in the gut. This can cause the fish to flip over and have difficulty maintaining any sort of buoyancy in the water. It may be worth switching their food. Move them onto a diet high in frozen green foods, supplement this with Daphnia (which is essentially a Goldfish laxative) and Bloodworm (once a week, Goldfish are omnivores but their natural diet sways more to vegetation rather than meat).

Sadly if it is Swim-Bladder then there is little you can do. Try dropping the water level to around six inches and gently raise the water temperature by one or two degrees. Alternatively a mild salt dip for around ten minutes may help (although, personally, I think Salt dips are useless).

Changing filter media is a no-no at this point. The filter pads are the heart and soul of the tank. The bacteria within them is vital to a healthy tank. When you clean the filter take the media out, wash it with old tank water and then put it back in. Carbon media will nullify any treatments you put in so it's worth taking that out if you have to medicate your fish in future.

Also, don't tap the fish. Fish essentially wear their immune system on the outside. They have a slime coating which prevents infection. Fungi spores are abundant in water and you may leave them open to attack if your a little too vigorous.

Swim-bladder usually occurs shortly after purchase and is usually associated with a rapid change in temperature or Water Parameters (the chemical make-up of your tank). Curing it is difficult and rarely successful, however, good luck.

Tom