Its very hard to see anything. But I don't see any powerheads, more flow will help stop detritus from settling on the rocks and also push more water through the filtration system.
I would say get more snails, especially turbo snails.
Be careful with feeding, feed only as much as the fish can eat in 30 seconds, if you see food being uneaten then you've added too much, rotting food feeds algae growth.
Besides that you should be doing weekly water changes, I do 5 gallons weekly on my 15 gallon, toothbrush the rocks and blast them with a turkey baster when you change the water, get all that stuff in the water and siphon it out.
Clean hob or canister filters often, change the filter pad every few days.
Just my 2 cents
