well today I got a free 5 gallon tank with filter, Heater, and hood. I know that not many fish can be keep in such a small tank so I thought Would get a Betta and some Otto's would that be OK? it is going to have live plants with 2.8 watts per gallon
Oh YES that would be wonderful! I have my Noel and 3 Otos (Sneezy, Doc and Tuck) in my 5 gallon and they get along just fine. I would however add the Otos first and get them settled in so they can get all moved in. This way maybe the Betta will feel that he is coming into THEIR home instead of them invading HIS. If you get the Betta first he will be a little pest when he has new neighbors. LOL They can be naughty when they are challenged on their own territory, so let them enter and find a territory when everyone else already has one.
I do congratulate you on the decision to rescue a Betta and some Otos. They are perhaps some of the most mistreated fish that we keep. If you would like more information on the mistreatment of the Otos you can go to:
Anything! Plants overall are great. However, something with broad and stiff leaves that reach near the surface are good, since they can sleep on them at night and won't have to swim much to get air into their labyrinth organ.
Lucky! I wanna free tank!
Just so you know, Otos are extremely sensitive to water quality. I have to move my Otos out of my 10 gallon because the nitrates stay around 20 which is fine for the other fish but the Otos came down with bad finrot because of it. If you want to try keeping Otos in that small of a tank you will probably need to make it densely planted and maybe do more than weekly water changes. You may have a better time with a few small Cories. Now I don't want to discourage you from getting Otos. I think in a 5.5g it would be easier to do larger or more frequent water changes. I just wanted to make sure you know this so you don't end up with sick Otos like I did.