I agree with everything amcarrig says. I used to keep sea horses and they need a tall tank to be happy. A 29g is a perfect tank for them. They also need to be feed 3 times daily as they have no stomach to speak of.
Live corals can also injure them. I used to use dead branching coral and plastic plants.
They also prefer slowly moving water. The 330 penguin may be too much flow for a 20g. I would go with a penguin 200 and a good HOT skimmer like the remora or bak pak.
Good luck! _________ 75g reef with Nova Extreme 8 bulb HO T-5 lighting, refuge, Remora skimmer, DSB, Seio powerheads, Acro's, LPS corals, assorted zoo's & mushrooms, Yellow Tang, Maroon Clown, Blue Cleaner Goby , Cleaner, Fire and Sexy Shrimp, Coco Worm, T.Crocea Clam, Derasa Clam
120g FOWLR, 260w Orbit power compact lights, Remora Pro skimmer, 30g DIY Sump/Refuge, DSB,Seio Power heads, Powder Blue Tang, Purple Tang, Flag Fin Angel, False Eye Puffer, Copperbanded Butterfly and a Moorish Idol |