Weather Loaches

Question
Hello. I had two small about five inch long weather loaches. I kept them in a ten gallon tank, with a red betta fish. One morning I awoke and found the larger of the two loaches with holes and gashes in it's stomach and back. It lived a few more days and died this morning. Do you think the betta fish injured him? The loach has mostly holes, and his stomach almost looked like swiss cheese. Thank you for your help!

Also, I do not know for a fact that it was a weather loach, as I got them from a friend. I looked up all kinds of loaches, and the weather loach looked like them.

Answer
Hi Sarah,
When fish attack other fish, it is mostly because the fish who is attacked is sick.  Bettas usually get along with loaches, but if the loach was sick, and weak then the Betta could finish him off. Fish have a way of getting rid of sick fish!  I doubt very much that the Betta would have killed him.  I think the loach had fungus, which rapidly grew on his body.  Check your water for ammonia, nitrites, and nitrates.  The ammonia level should be zero, or safe, the nitrite level should be zero, or safe, and the nitrates should be low.  Ammonia is the number one killer of fish.  You can buy these small test kits at your pet store or Walmart, and they are very handy to have.  Make sure that your gravel is fine, so that the loach does not hurt himself on pointy rocks.  They love to hide in the gravel, so it must be very fine.  If the loach hurt himself, and it went unnoticed, then fungus set in, and this is what could have killed him, but check your water to make sure your water chemistry is right.
Hope this helps
Lynda