Mystery Death...

[sa1sa]

First problem:
I have a 10 g with good filter (aquaclear) and right air pump. The tank had been cycled for a week so i start adding 1 red cap in it (about half a thumb size). Everything seems good for a week so i added 1 more goldfish. About 1 months, i have 4 small goldfish in there. so i decided to add live plants (cabomba) n a small pleco. Then, the goldfish starts to lay on the gravel and, one week later, the fishes are dying one per day. Checked the water quality, and it was perfect. I know a 10 g is small for the goldfishes but i dont think that's the cause of the death (well, not in 1 month). i do water change (25%) every week, n do it more often when the fish are sick. Im suspecting that it was the pleco that spreads some kinda diease because before i added the pleco, everything was fine.

Second problem:
After the tragedy, i setup a new tank with the cabomba (everything else washed, Cycled, checked water,), n start adding one small orange oranda. Two days later, the fish stays in the upper corner for most of its time. 4 days later, it die. So i brought another oranda in there and the symptom occurs again in the 3rd day. So i put it into my 5g hospital tank but, 3 days later, it die. Dont think it is swimming bladder disease because it swims fine. temperture is right for goldfish, and the air pump (up to 10g) works normally. I did a lot of research in library and on internet so im pretty sure i did everthing correct. even asked the salesperson in the pet store, they dont even know why.

Im currently setting up a 30g, hoping it wont happen again.

 

[K.J.]

The reason: too much bioload. How did you cycle it? You see, a 10 gallon wouldn't even be suitable for one goldfish or one plec; fancies need a minimum of 20 gallons for each of them and another 10 for one added after that, and some say double that. Plecs AND Goldies are massive waste producers so even with a good filter you really couldn't do anything. Don't add all of those fish to a 30G; consider going tropical or just adding 2 fancies

 

[smmetz]

When you checked the water quality, were you able to check the ammonia and nitrite levels? If they were high, it would indicate that the tank was not fully cycled. Sometimes there is confusion about what cycling means. Some think it means running a filter in a tank for a few days or a week, with no fish in the water and no source of amonia. Without adding ammonia drops or a fish to provide a source of amonia, the tank will not "cycle". Cycling has to do with the nitrogen cycle. There are types of bacteria which break down ammonia into nitrite, and nitrite into nitrate. Ammonia is the most toxic to the fish, and nitrate is the safest for the fish. Weekly water changes are not usually adaquate to control ammonia levels if that bacteria is not present. A "cycled" tank means that there is a balance of ammonia sources (fish), and the bacteria to process that ammonia waste. When someone runs a filter in an empty tank, there is no source of ammonia, so that bacteria does not actually grow in the tank. (ammonia is its food, so the bacteria has no food)

Anyway, sorry if I overexplained the basics of it or repeated myself. For more details on cycling a tank properly, I recommend this thread:

http/www.fishforums.net/index.php?showtopic=10099