Watching the marine betta more closely during feeding times (I don't have the plank set up yet so I'm hand feeding daily) and he's such a docile eater. One of the things I found in my pony research is that as long as you're not doing dwarf (or very small juveniles, or are worried about breeding and raising) the marine bettas actually make a really good companion fish for the seahorses. They only want to eat smaller things that fit in their mouths, and *most* of them are very calm eaters. Many fish don't make good companions in a seahorse tank because they're such voracious eaters and essentially out compete them. One of the well reputed vendors has a section of compatible fish and they're on the list. I doubted it at first but the more I watch....
I might end up keeping him in this tank long term to go with the pair instead of moving him back over to the bigger tank. I keep saying it's "the small tank", but it's still about 60 gallons which is suitable for the marine betta. I've never seen him go after a fish, just shrimp & nudis. He doesn't even go after the snails, that's the duskys business.
Trying to figure out what to do with all my remaining rock....