dead goldfish

Question
Hello! We bought our son a Marina goldfish tank for his birthday. We set it up on the Monday night, rinsed everything going in it, put in the chemicals, ran the filter. We bought 3 goldfish on the following Saturday, on the advice of the pet shop, and introduced the fish to the tank as per the instructions. One of the fish was dead by Sunday, the remaining 2 died last night (the following Sunday). While alive, they were very lethargic, rarely coming to the surface, so I did a 25% water change and chemical addition every 2 days, and only fed them every 2 days. My husband said that they seemed to have some sort of film on their scales when he took them out of the tank this morning. What do I have to do to make sure our next lot of fish don't meet a similar fate? The chemicals are aqua plus and cycle.

Answer
Hi Sarah,

The white film on the fish depends entirely on how long they were in the tank after death. If removal was pretty much immediate then it would suggest that they were suffering from some sort of skin condtion ie, skin flukes or a parasite infection. If removal was delayed (Monday morning say) then it likely that fungal spores had begun to take advantage of a free meal.

Fancy goldfish have no stomach so they produce vast quantities of ammonia. Added to that they pass highly concentrated urine into the water frequently, further affecting the ammonia levels. Add all this to the fact that a new tank slowly becomes full of ammonia and you have a Goldfish Graveyard.

Use activated bacteria to kickstart the filter bacterial colony and add one Goldfish first. Perform 50% water changes once a week and then switch to 25% fortnightly after the first month. Goldfish need at least 10L to themselves so make sure overstocking doesn't occur. Keep the surface water rippled to allow optimum oxygenation of the water and provide a well varied diet.

Tom