I have a big killifish that is greedy too. I just scatter broadcast enough food for everyone. I have read slow or shy eaters don't get enough. (African frogs among others). Have to set it in front of there face.
Yeah the vision barriers don't always work ---really need a lot of them. One of my tanks is that way. Ridges, valleys, nooks, tunnels, plants, so smart fish can can hide when they want. Some people like open tanks. I like both.
You mentioned using Prime. A few years ago I came across Safe. Same thing as Prime, made by Seachem also. They made it for big tanks. (I worked the math down so you can use for small tanks.) It is concentrated in powder form. Just add appropriate amount to your fresh water change water. A bottle lasts 6months to year. Saves a lot of money I bought a set of miniature measuring spoons to go with it for under 5 bucks.
Yup there is usually some kind of drama going on in my aquariums too.
You mentioned switching tank mates. Have you tried every combination?
Pretty much...here's the rundown
Boss / Patch / Kong = rumble, later tag team on Boss
Boss / Kong = Ok at first, went downhill when Kong established dominance
Boss / Patch = Ok until Patch laid eggs. Seemed to like Boss up until that point
Patch / Kong = Never was great...Kong kept going alpha on her. She sliced his lips one night.
Boss / Brick = Passable. Boss isn't an outright bully but he's a punk sometimes. The new tanks have him spooked though.
So basically
Patch with anybody = injuries
Kong with anybody except Patch = stress
Boss with the other two = injuries and stress
Boss with Brick = some bumping and pushing at times.
As I mentioned before, I think the dynamic with Boss and Brick is going to change in another month or so, especially at the rate Brick is growing.
Good news, though! Patch and Kong are in their new homes and they went completely berserk with excitement for 40 minutes, dancing along the glass. So the tanks are a hit...I finally put the moon light on as a signal to calm down and rest.
Meanwhile Boss and Brick floated in the center of the main tank and watched the setup and activity.
The one thing I didn't account for was the influence of the sand color...in the smaller tanks its so powerful it pretty much dims out the backgrounds. I thought something had happened to the leds at first. The warm white turned everything nearly yellow in Patch's tank (with the green sand).The Baja blue is a gorgeous color...and turned the background nearly black, lol. Completely different effect than the earlier pic I posted without the sand. Kinda embarassing an artist forgetting the influence of light and color on backgrounds! You can see highlighted areas from a distance but that's it. I think the type of led's on the smaller strips are a bit different too, they look 'harsher' and less true than the larger strip and have a more limited spectrum range. I think this is why the weirdness happened with the backgrounds. Gives them a lot of depth, tho.
Fish profiles and pics will be coming soon.