Betta staying at the bottom of the tank.

[BlueBetta17]

My male betta was fine before I added in two Platies with him. They are in a 3gal tank. All of the fish are healthy, but I noticed yesterday my betta started laying at the bottom of the tank. It's heated, and I feed them every other day. I think the issue might be that the other fish have caused too much ammonia in the water. I took the Platies out and left him in there. Do you think that's the reason? He's still staying at the bottom but will swim and eat when needed.

[sainthogan]

Did you change the water after removing the platies? If you suspect ammonia, you need to change the water immediately. It can kill him or cause serious permanent damage. Also, get a water test kit, so that you can actually measure the amount of ammonia in the water to avoid this situation in the future.
Adding new fish can cause the ammonia to spike, and spikes can be deadly.

[DragonFish]

+1
You'll definitely want to preform a very large, if not a 100%, water change if you suspect the cause to be high ammonia, which is very possible in such a small tank with so many fish. Just taking the other fish out won't eliminate whatever ammonia they have already put into the water.

[BlueBetta17]

I did a 75% water change tonight. And I plan on doing 25% water changes every other day. Should I do changes each day? I have a divider in the tank. It's a total of 5 gal, but my female on the other side has been unaffected. Is that weird?

[DragonFish]

....Well that definitely makes a bit of a difference, knowing the full volume of the tank. xD
That sounds fine. The 75% change should have brought down the ammonia. The 25% change probably wouldn't be a bad idea though still, if only as just a precaution.

Is your tank filtered? How long has it been set up?

[AyalaCookiejar]

It's a good idea to get a test kit if you don't have one so you can be sure if it's ammonia or not. That's really the only way to know if 25% water changes every other day will be sufficient. Also, since it's divided and there are two fish the ammonia is still going to build up faster anyways.

I don't think that is necessarily "weird". Some fish just react differently to things than others. There are odd fish who can survive a long time in water that is never changed. I'd monitor him since you just did a water change to see if he gets better and watch for other symptoms.

[BlueBetta17]

Thanks for the help! The tank has been running for about 2 weeks. It doesn't have a filter, but I normally do frequent water changes. It does have a heater though and I don't overfeed. The divider is glass, so maybe that is why my other better hasn't really been affected.

[AyalaCookiejar]

Have you been doing 100% water changes?

[BlueBetta17]

They have been 50% water changes that I do normally once a week. And 100% changes every two weeks.

[AyalaCookiejar]

Sounds like you are doing good there. It's still a good idea to get a test kit, although it is not 100% necessary. It helps to figure out problems like this. The API master test kit is around $30 but you can get the 25 test strips for about $20. The master test kit gives you around 800 tests and well... you can do that math :p It is expensive but it will last a pretty long time.

Since you just did a water change, it's best to just observe and see if that helps. I wouldn't go into panic mode if he is still eating and has no other symptoms... as long as he periodically comes up to breathe :p and those 25% water changes sound like a good idea, as well.