It really depends on him. Since he is a half giant, it makes it more iffy. I have a giant in a 10 gallon currently, and I know he makes a lot of waste!
Is the tank cycled? Do you have a testing kit? If not I recommend API Master Kit which is 100% better than the strips.
Shrimp tend to be eaten, snails tend to be messy... A 10 gallon is really hard to find compatible fish for. Tetras can be nippy, or he may attack them. Female guppies (less colorful) may work, but again it really depends on his temperament.
If you do buy fish for the tank, find he is very aggressive or they are aggressive, do you have a back up plan?
Well he seems to be a pretty mellow happy fish and is rather silly at times, The tank is cycled everything is within it's levels last I checked yesterday, I thought about ADF, but I read that they can come with a rather nasty fungal infection that can kill them within 3 months, for one I don't want to house the frogs for 3 months to see if they don't have this fungal infection and 2 I love my king and I wouldn't risk getting him sick or worse. I thought about shrimp but again I bet he would most likely eat them plus they are very easy to kill by not being on top of the water conditions. So I was hoping someone with kings would have some suggestions as to what they have had sucess with otherwise poor elvis will live alone......
Well, it is not so bad if he lives alone :p I don't think I rust my giant with anything other than a female when breeding time comes around I never knew that about the ADFs... I had one, the one problem I had was he would nom the fish's fins :/
Well the problem with the fungal infection come from pet stores keeping the dwarf frog with the claw toes frogs the clawed toed ones are immune to the fungal infection and carry it while the dwarfs are not immune to it and die from it and it takes up to 3 months for it to kill them so the petstore owner may not even realize whats going on.
I have a giant, still a baby at only 2.5 inches, but still def a giant too in a 10 gallon heavily planted tank. Like so heavily planted I sometimes can't find him in the tank. I also have shrimp in that tank. Just some little ghosties. Since I sometimes can't find him, you already know I can't find the shrimp most days. But they are still in there after almost a month of having him. At least some are. Again, I couldn't give you a number since I couldn't find them all if I tried. Otherwise I don't think I would put anything else with him. I am fully aware that he could eat the shrimp. I am also fully aware that if he wanted to take a chomp out of anything he would probably mortally injure it with the first bite. His mouth is just huge. So keep that in mind if you get anything else!
Lots and lots of plants will also keep the water quality good so you won't have to worry about the shrimp. Though if you do get a floating plant like frogbit, make sure it doesn't cover the entire surface of the water if it grows well. :)
I would think that with a betta's eyesight (I've read it can be fairly poor) in a 10gal you could do ghost shrimp. They're totally transparent so they don't stand out hardly at all. I'm hoping to get some of these myself when my filter and therm comes in and I can begin cycling my tank.