Newbie error to avoid

[chadthedad]

Well I was sooo proud. My cycle was complete and I added fish. Things looked great. I did a large water change prior to adding fish. I checked my ammonia and nitrite which were both at zero. I then acclimated and added fish....

The error. I assumed that since I had just done a large water change that my nitrate must be low so didn't bother testing it. 36hrs after adding the fish I lost three. Tested ammonia and nitrite (which I had been doing twice a day to ensure everything was going well) both were at zero. Nitrate was around 80+. Did a 50% water change which brought it down to 40. I waited a few hours and did a second 50% water change which brought it down to 20. I lost one other fish in the process. Still have a couple that don't look great but hopefully they will come around.

So... Just because you did a large water change after a fishless cycle the nitrates may have risen so high that they are still in the danger zone. Make sure to test that before adding fish.

[SpeedEuphoria]

Yeah I've never done the fishless cycle but I would recommend doing a very large water change the day before, like 80-90%, then you should be good.

[neilanh]

Agreed, the bigger the better at that point.

However - I wouldn't automatically assume it was your nitrate level. While we prefer to keep the nitrates below 40ppm, fact is they're not toxic until well over 100ppm. Assuming you did a good acclimation, it could have been that you just got weak fish. Think about what a fish goes through before you buy it from the store.

You'll probably never know for sure, and at this point it probably doesn't really matter either I guess.

[MichaelsLilGray]

it would also depend on how hardy the fish are to began with. If you had rather peticular fish.. it may have been what did them in. However if the fish can withstand pretty decent ammount of temp changes, ph's and ammonia levels.. you probably got ahold of bad fish.

[chadthedad]

I lost two neons (they were pretty small and I don't think they are as hardy as some people say they are) an otto and a boesmani rainbow (it looked a bit week from the start).

The rest of the fish seem to be doing well. The two that looked a bit out of sorts were more active this morning.

[meegosh]

I agree neilanh, It was probably inferior quality fish combined with the stress of moving into a new home. I had picked up 6 neons and added them into my 30g when ammonia and nitrite were at 0 and nitrates at 10ppm (regular for my tap water) and 4 ended up dying with the first 48 hours. I'm not sure about the rainbow or otto but I know neons are not as hardy as the used to be.

The neons I see are rather pale in color compared to my 6 that I have in my tank. They are a very dark, almost purple, blue and a really nice bright red. It took probably 3 weeks of a high quality diet for them to start getting darker.

I would keep an eye out and don't beat yourself up about it

[Purrbox]

Both Neons and Otos can be quite touchy, so it very well could have been just those fish that was the problem.