You could also get a Nerite snail. They suck algae, come in different designs, and usually their waste and all is pretty low for a snail. Most bettas usually get along with them and they don't reproduce on their own so you don't have to worry about a million snail babies if you get one. But they eat algae fast so you should buy algae wafers too.
Milo : Crowntail, SIP;-;, Vivian : Crowntail SIP, Kawaii SIP, Kano : HMPK, Igneel : Halfmoon, Atlas : Feathertail EE, SIP, Magnus : DTHM, Avian : HMPK, Juno SIP-Delta,
Alias-HMDT ,Blu-Delta, Tanso : Wild Smaragdina,Neslet-HMRT, and Hetalia.
Calico-Shubunkin and Comet-Comet *DECEASED*