What tank mates should I get for my Betta?

So my Betta has developed a problem with tail biting, and I am trying desperately to correct it. I figured I would give a tank mate a shot because I heard those can help, but I never intended to have more than a Betta when I set up my tank. It is only 5 gallons and is consistently at 79-80 degrees F, and it is also planted. I would really like some type of bottom feeder fish, like a catfish, but everything said I needed at least 10 gallons to do that, so I guess I would only really be able to have snails or shrimp. Problem is, all the tank mates that are recommended for a 5 gallon tank have different water parameters than my Betta (mainly they like lower temperatures than 80 degrees). Like Nerite snails for example were my favorite option, but they do better in water under 78 degrees. I need something with a low bio-load because my filter is not the greatest, so definitely not a snail that can reproduce on it's own. The closest I have found to something working would be to get 3 ghost shrimp. I am frustrated trying to find something that would work in my tank. Does anyone have any suggestions?