Urgent Help Needed With Tank of Tetras

[RewindsRetro]

Hi everyone,

I have a tank of 12 tetras, 6 neon and 6 neon black and 2 small apple snails. I just did a 30% water change and everything was fine, tonight the neons are acting normal but the neon black are gasping at the top for air. I immediately did another 25% water change and for an hour they all seemed fine and then they started doing it again but less continuously. This is only affecting the black neons still... I do not have an air pump or air stone or whatever but I read several places they didnt need them with a proper filter, which I believe I have. I don't want them to die, i've grown attached... what can i do tonight in the middle of the night to stop this?

I use Prime conditioner in the water before I change it, and the filter is the hang off the back filter that came with the tank with a brand new filter when i did the water change, Tank is heated to a consistent 75 degrees. With one live plant and a few caves.

And please don't judge me but I got all high and mighty over how well my Betta tank was doing and I jumped into having this second tank full of tiny fish before I had it properly cycled, it was dumb, like those getting your kid a bunny on Easter dumb, but now I have them and they are not going to suffer for my stupidity, so that's why I am here.

Water levels with test strips are in the normal range with the exception of hard water which is high here. They were fine for 3 months with those conditions.

 

[charliebankston]

How often do you do a water change?

 

[Aiken Drum]

When you say water parameters are normal, could you give the numbers please. Also, how big is your tank.

I would recommend using a liquid test, rather than strips. Liquid test is more accurate, and as you get 100s of tests from a liquid test kit, they more cost effective too. API master test kit is a good one to go with. It covers the basics and is considered reliable.

You have mentioned not having an airstone because of your filter. Does your filter provide good surface agitation for gas exchange and oxygenation?

Might you have forgotton to add water conditioner when you did your water change?

You have already conceded that the tank isnt cycled though, so testing and water changes are your go to solution. Test daily, if you see detectable ammonia or nitrite, do 25% water change. Keep this up until you are consistently seeing 0ppm ammonia and nitrite and your nitrates are rising. At this point you will be cycled and you can cut back a little on your testing/water changing routine.

However, saying all that, if your tank has been running for 3 months it probably is cycled now. Ammonia poisoning is slow acting, so possibly previous poor conditions is now catching up with your fish.

Possibly changing your filter caused a cycle crash. What exactly did you replace? Its normal to just rinse these things in tank water or dechlorinated water, if you replace them you lose beneficial bacteria. The only thing you want to be replacing are polishing pads and chemical media (activated carbon normally).