Are Ants toxic to Bettas?

Question
I have asked many pet store employees that if a betta eats an ant will it cause the betta to die from it.  No one seems to know the answer but the reason I ask is because it has happened to me twice, where the betta was doing fine and then notice that an ant is floating in the tank where I believe there were others and the betta must have  ate one.  After noticing the ant, one day later the betta loses his appetite, and the 2nd day the stomach swells up.  This pattern has happened twice and I just found out that it also  happened to a friends betta tank as well, where there was an ant problem in the house and they found one floating in the tank.
Is the ant  being in the water causing them to get sick or did the betta have to ingest one?  Also is there anything I can use near the tank to divert ants from wanting to get water from the tank.      I have another two tanks with bettas in them, and I am constantly being on "ant patrol" and its driving me nuts, and I just want to know if I am worrying for no reason, or is my theory about ants being toxic to bettas justified.
By the way Chris.... I think you are a great fish expert, and I truly enjoy reading your answers.

Sincerely,
Anne

Answer
Hi Anne;

Thank you so much for the compliment. I really appreciate it. ;-)

I've never heard of a betta having a problem after eating an ant, but perhaps they do it and we don't see them? I guess if the ant were to sting or bite as it goes down it could cause irritation. Bugs are a betta's favorite food actually so it seems weird that they would hurt him.

There are a couple of creative ways to keep ants away from the betta tanks. If you have a shallow pan that the tanks can sit in, put the tanks in it and put water in the pan. It forms a "moat" that ants can't cross. If there are cords that ants can climb across, put a barrier of petroleum jelly (vaseline) around it. You only need a ring of the stuff an inch or two wide. You can also put a petroleum jelly barrier around the bottom edge of the tank instead of the water. You could set the tanks on a plastic placemat or something so the petroleum jelly doesn't touch your furniture. Be sure that the tanks aren't touching anything or anywhere else for ants to climb over.

Oh, and it works for pet food dishes too!

I hope these ideas work out for you......

At Your Service;
Chris Robbins