Why is my betta fish acting this way?

Question

1 have a 100 l fish tank. It was empty until I bought one male betta fish. After a month or so I bought 10 zebra danios and 2 borneo suckers. Since I put the zebras with him he started acting strange. Like he doesn't like them. He started darting around in the tank and since yesterday he's not eating and his fins are clamped. The zebras are fine and the borneo too. I have noticed a little whiteness on one of his fins which I'm not sure if he's damaged while acting this way. Ive put some medication against fin rot in the tank. I am really worried about him. I separated him into a smaller tank and put meds in it too. I am not sure if it's ammonia poisoning but I assume its not as I barely have fish in a 100 l tank and they are really small. I do have a test but I didn't realize I run out of ammonia tests and I only have a 6 in 1 test which all turned out fine when I tested the water. I will buy some more tests tomorrow.

I was really thinking that maybe he's highly stressed because of the zebras fast swimming? They also swim at the upper part of the water where he likes to build his nest. What do you think? I have a filter and a heater too it's on 26 degrees. I also have only live plants. 

Update:

Ahh, thank you! U cant believe I was so naive to think they will get along well and I always inform myself before buying a certain type of fish. This time I just assumed they are a bit fast but peaceful fish. I am setting up a new 5 gal tank for the betta.

Answer 1

Betta fish should be the last fish you get. If you get any more after them then they can start acting strange as a sign of jealousy.

Answer 2

You need to test for ammonia, nitrites, and nitrates. If you have anything other than zero ammonia, zero nitrites, and a low nitrate reading, your tank is not cycled. It doesn't matter what fish you have in the tank with regards to ammonia or nitrite poisoning, it depends on how much food goes into the tank. How often do you perform partial water changes?

There could easily be fin nipping going on, but the overall symptoms you describe sound like water quality issues.

Answer 3

Often caused by a lack of oxygen in your 

betta's

 water, hypoxia can cause your 

fish

 to swim in an odd 

way

. Most often they will spend a lot of time at 

the

 surface of 

the

 tank trying to get oxygen. However, it can also be caused by gill disease and anemia. (Hypoxia can often occur when 

the

 water is too warm.

Source(s): https://iqosdubai.ae/

Answer 4

The danios are taking nips out of his fins when they dash by.  He needs his own bowl away from them.  He'll do okay with a non-nippy fish like a couple corydoras catfish. 

Answer 5

Zebra Danios should not be kept with Bettas for a couple reasons. One is that they are fin nippers, and will bite chunks off of a Betta's long fins. That can then get a secondary infection like fin rot. Also, Bettas tend to be alarmed by fast moving fish like Danios as well. So not only do they freak him out, but they will hurt his fins. They just aren't compatible tank mates.

Answer 6

Zebras and bettas do not get along bettas are afraid of zebras they see them as predators

Answer 7

Betta fish are very aggressive and do not like company.