help :(

Question
Oh thanks but unfortunately its too late. :( I found him dead about an hour ago.But I'll make sure to help the others. I do have a heating thermometer thingy. Is it really safe for them? I always feared that maybe it would burn them if the got too close. One of my fish's body looked burned when I had that thing in there.
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Hi Diana;

Some bettas can't be kept with other fish at all. They are terretorial by nature. Many do very well in tanks with other tropical fish, but it also depends on the size of the tank.

I think the problem with all your bettas right now is too low of a temperature. Bettas are tropical fish and need temperatures of 75 to 82 degrees fahrenheit 24 hours a day. They get sluggish, develop infections and some can't digest their food and die from intestinal blockage if too cool.

Get the temperature up for the sick one. Put a light on him or some other heat source and try to get it up to 82 or even 85. It should help his infection heal. Use a fungal remedy at the same time. Also keep his water very clean. Bettas need their water changed once a week in containers that are 1/2 gallon and larger. If they are less than a half gallon it will need to be twice a week.

Here are some sites to help you further on betta care;

www.healthybetta.com
www.bettatalk.com

At Your Service;
Chris Robbins  

Answer
Hi Diana;

I'm so sorry you lost him. Sometimes there just isn't much that you can do.

A thermostatically controlled heater is safe to use if the tank is 5 gallons or higher. Look at the wattage on it too to determine what size tank yours is for. You need 5 watts per gallon of water. If it has too many watts it could overheat quickly and easily kill the fish.

At Your Service;
Chris Robbins