Help this newb with her neon tetras :(

Xela

I got neon tetras about 3 days ago, 6 of them. ive had them before but unsuccessfully. they're in a 30-40L tank and the temp is at 24-26 C. Last time some of my tetras went this way... they started looking like they were "light" like, they'd float to the top of the tank go upside down etc but still be breathing. one of them went like this yesterday and died another one has gone like this this morning so I have put him in a tank on his own... other people ive asked have said its stress but i cant see what id do to make the move less stressful for them. I leave them floating in their bag in tank for 20 mins, put water from tank in bag for 15 then release them. I havnt got test kits for my water for nitrate ect or PH lvls reason for this is i live in Christchurch, New Zealand and our water is untreated and said to be the purest in the world - weather i should still be testing for nitrate ect i do not know? and as for PH levels i was told that it doesnt effect neon tetras too much, apparently theyre hardy in that aspect? and Also one of them who I have just segregated has had its tail riped/bitten off !! there are no other breeds in the tank. just 3 neon tetras left that are looking healthy thus far, i know i should keep them in larger groups but am reluctant to get more buddys for them if theyre gonna go the same way! It sounds like these dudes have Neon Tetra disease i got this last lot and the lot before hand from the same place. the fish there always look healthy and lots are kept together in a big tank. how would they have developed this? what should I do :( please help

Xela

Hmmm.. one of my segregated fish has died so i disposed of him. the one with no tail is still alive but ive found another fish whos been just swimming on his own so decided to put him by himself also ... he seems to have white spots on him, whether the fish that have died have had this i havnt noticed and have disposed of them now so cannot check. none of the healthy fish or the one with no tail have this.

Falina

It's very important to test your water for amnia, nitrite and nitrate, and ph is very useful to know as well as neons don't generall adapt to harder wter too well, though they can do if acclimatised properly.

Amonia, nitrite and nitrate occur when the fish waste breaks down. it doens't matter how good the water is to start with, this process happens when the waste breaks down and so it's vital to know your parameters.

If you want more information on the cycling process, there is a great sticky by fish4all in the starting and maintaining section that explains it all well for you.