80g low maintenance no sump project help

[needlehandssoftfingers]

as title says, im interested in sea horses and most setups so id appreciate some ideas for this project. for example, i do like small eels but i know theyre too messy of eaters for me to easily maintain with just rock as filtration (unless im wrong here to, there seems to be so much nuance) at most maybe a seapora HOB skimmer? same for seahorses since they mostly eat high protein shrimp etc or am i wrong here too? even finding a comfy spot for the pump on this carbon reactor on the 80g feels bad, do i need carbon for a light bioload and 75 lbs rock?
thanks for all responses, not sure where to take this tank as i dont want to sell it when i upgrade it in the spring. not drilling it so options seem limited to small fish and a tang?
wouldnt mind something a lil different w this one

 

[Spare time]

Rocks are not a filter. They ae a house for bacteria and handle ammonia/nitrite (nitrate to a tiny degree). I would still highly recommend some form of mechanical filtration and a place to run carbon. A refugium would be fantastic. Low maintenance and no sump are often opposites.