Disaster Strikes - Surprise Blessing

I knew those cardinals was a bad idea! Things have gone dramatically south. I found another cory with a mysteriously cloudy eye and pale gill plate revealing reddish gills, yet on the other side of his head he was perfectly normal. I am not terribly experienced with cories but a unilateral illness seems odd to me, especially since it looked exactly like the ailment suffered by the first cory casualty I had, both times on the left side of the head.

I therefore decided to treat the tank with Melafix, and after doing that the rest of the tank began to suffer. I don't find anything published about Melafix being harmful to anything but labyrinth fish, so I did not expect this, but the Boesemani rainbows began to act oddly, gasping at the surface, and over the course of about 2 days the entire tank was doing this. I cannot find any abnormality on multiple test kits - no ammonia, no nitrite and only trace nitrate. This tank was essentially cycled silently due to the same decor and the same fish, along with the powerful filter from the 55 running in concert with the new filter. I did not detect any blip in the water params after adding the cories. I have been testing over and over, since the fish seem to be acting like nitrite poisoning. I did a PWC and lowered the water level, and now I have even added a bubble wand at the filter outflow, since they seem to be struggling.

For insurance, the tank had a dose of BioSpira added when I added the cardinals, and I trust that stuff to cycle any tank - I've done a lot of personal study on this product, and engaged in many online debates on the fish forums in years past about this stuff when it first became widely available. I am sold on it and am very grateful to have it available, though with multiple tanks I have not had to use it in many years. I had taken down several tanks at the same time, revamping my collections across the board, and found myself without a supply of bacteria. As long as you add the correct amount for the fish load (this needs to be carefully thought out) it will cycle your tank.

I have lost 3 Boesemanis and a couple of cardinals. A couple of the Endler's look bad but the majority of them, as well as the guppies, are acting normally. The cories are acting normally.

Last night I did a 50% PWC and am no longer adding Melafix, and the fish seem happier, as if the water was somehow toxic. I still have one rainbow that appears to be heading for the end, but 2 are acting normally now. I can't think of what I have done, but adding too many fish too soon is ultimately the reason. There are too many possibilities, even though the typical issues associated with overstocking are not present. From now on I will quarantine new fish, and add them more slowly. I erroneously thought that with this large of a tank, with this much water volume, I could add more fish at a time than I would have in a smaller tank, but something has upset the equilibrium, and the premature addition of new fish has got to be related.

Incidentally, the ailing cory was found dead, wedged against the heater. This was something that had occurred to me when I saw the nature of the left-sided wound/ailment. I thought it might have been stuck against the heater. There is no reason for this - I know that sometimes plecos have this happen, suctioning themselves too close, but why the cories would be crowding around the heater is beyond me. The thermometer is currently mounted at the other end of the tank, in the front, as far from the heater as possible, and the temp is at about 76. I have moved the thermometer around, up high, down low, one end to the other, and cannot find a spot that measures any different than the next spot. The tank seems to be quite evenly heated, in other words, so that the cories would not tend to huddle around the heater.

I have a crazy theory about the cory cat ailment. Cory cats tend to move around the tank in little gangs, following certain paths. Up over this rock, down behind that plant, following along the back glass, and around again, like that. Maybe they would travel under the driftwood arch, which hides the filter intake basket (a very large object) and the heater. If they were moving through there and were startled, they might choose to dart behind the filter intake basket, encountering the heater, and get stuck there. This is what came to mind when I had to extract the dead cory from between the glass and the heater, with the left side (same side as the wounds found on two cories) pressed against the heater. I moved the heater away from there, needless to say.

There is nothing to do but speculate. Repeated water parameter testing is normal - dead normal.

Now on to the Surprise Blessing. Speaking of revamping my tanks, I had taken down my 40-gallon ARLC (African Rift Lake Cichlid) tank, and sold off the Africans, along with the Buenos Aires tetras I had for dithers. Since the tank had a history of cyanobacteria issues, I removed all of the old substrate, sterilized the tank, put the rocks out on the deck for a week in sub-freezing temperatures after scrubbing, and sterilized the filters. Starting over from scratch, I used Play Sand for substrate, a few of the rocks from the old setup, taken from the deck, and a few plants from the 150. I purchased several other plants to go in this tank, and I decided to sit on it for a while and let the plants get established while I decided what to do with it. I believe this is going to be a South American Puffer tank, so I wanted to have time to get a snail colony going in another tank to supply crunchy food for the puffers.

After it had been set up for a couple of weeks I decided to test the water, just for the heck of it, and what do you know, off the chart nitrite, and high nitrate. Why? I had not added anything but plants and some clean rocks and driftwood. This was odd, but something must have been in there decaying to provide ammonia to create this cycle. I still do not know what it was, though it would have had to be something significant to get those levels of nitrite. Very toxic levels. Oh well, I could not get an answer to that, so I kept waiting. The levels came down, finally, and I added some ramshorn snails since I had so many extras. They have been tooling around in there happy as can be, and now the cycle seems to be complete. No nitrite and trace nitrate. Perfect.

Yesterday I was looking over at the tank and thought there was more floating debris than usual, and what do you know, I recognized that the debris was fry! There are six wee tiny fish fry in this tank, near the surface, darting around. They are glass clear, though today I am starting to see the hint of coloration. One seems to have a stripe running down the side, like a zebra danio would, and another has the merest suggestion of a triangular dark marking on its side, like a Rasbora heteromorpha. I am really pushing it, since these are so small, but it is fun to wonder what they are. I would love some Het rasboras.

Rasboras are a good possibility, since they lay adhesive eggs on crypt leaves, often, and they do not scatter their eggs. I think eggs rode in on some plants (snail shells?) and were able to hatch. I don't have another explanation. When I discovered them they had obviously been hatched only a few hours, possibly a day.

I feel like such a newbie now - making newbie mistakes and having so many mysteries to solve that should not be mysteries, but there you have it. At the end of 2008 I was bored with my same old tanks that had been chugging along, stable for years, and wanted something new. Now I have it! Fish are dying off mysteriously, and fish are hatching mysteriously. Lots to keep me interested.