Much thanks for any help or advice on my latest goldfish problem. I have a pair of baby orandas, each about 2 inches long in the body, which I have had for 4 months now. It has been a nightmare, basically, with one problem after another: problems with cycling the tank, with ich, then a mystery disease that involved a lot of bottom-sitting and heavy breathing, which I thought was probably blood poisoning or gill damage from all the cycling problems I had been having.
The fish made it through all this, thankfully, but now one of them, the smaller one (Tangerine) has developed a new problem. For a while he started to swim awkwardly, sometimes rolling over on his side, and sometimes completely flipping over and doing a 360 in the water! We also noticed that he seemed to have trouble going very far down in the tank, or at least he never foraged at the bottom or went more than a few inches below the surface.
We thought it might have been SBD, due to over-feeding or constipation, so we fasted the fish for a few days and fed the fish much less (although we had not been overfeeding them at all before this!). This worked right away- Tangerine stopped swimming strangely, and started poking around at the bottom again after he was fasted and fed less.
Problem solved? Unfortunately not. About 5 days ago he started sitting on the bottom. His fins were erect and he looked fine, but he would just sit there. When I would come home or go over to the tank he would perk up and swim about normally, but after 10 minutes or so he would go back to the bottom and hang out.
I tried not to worry, because perhaps he was just feeling contemplative or resting or something, but it has gotten worse- now he lays on the bottom all of the time, and never swims around. Sometimes it looks like he is trying to get up to the surface, but can never get more than 6 inches or so off the tank bottom. He also sometimes breathes convulsively.
We have them alone in a 20 gallon tank, with under gravel filter only. We have been having lots of problems getting the tank cycled, even though it has been running for 4 months now, due to all sorts of factors. So there have been spikes of ammonia and nitrite every now and then when I get busy and forget to check every few days to do extra water changes or drop in some Amquel+. Also, the pH has had a strange tendency lately to plummet suddenly dropping from a nice 7 to around 5 or below. We have been adding baking soda slowly to buffer this and get the pH back to around 7.
I am SURE that it is not caused by parasites; the tank was salted at 0.3% for 4 weeks about a month and a half ago, due to the ich, and nothing has gone in the tank since except pure water and new gravel, which I washed very thoroughly. The extra gravel was added on a hunch that perhaps the cycling problem is due to having too little gravel or having gravel of too large a diameter- so I added another 10 pounds of finer-sized gravel, which should help boost the bio-filter.
The other fish, Mandarin, is fine, and seems perfectly happy though he often visits Tangerine and seems curious about why he is so abnormally inactive. We are going away for a vacation soon, and hope to have this latest mystery solved before then- any ideas on what this might be? Is it SBD? What can we do! (Tangerine is not eating at all at this point.)