Seahorses in a 20 tall

[augustasalty]

Hi. I have a 20T plumbed into my 90 Reef and 30 gal refugium. I was wondering if this would be a good tank for sea horses? If so, what kind of decor will i need?

 

[rayjay]

Other than dwarf seahorses it's generally recommended to have 29g minimum but I think some have lucked out with a pair of Fuscus in a 20.
It's not recommended to plumb to a reef tank as temperatures should be kept at 74°F to reduce losses from bacteria.
Bacteria like vibrio multiply more rapidly the further above 74° that the temp goes.
In the wild, the seahorses don't have a problem as the bacteria density is insignificant compared to how it develops in a closed system like our tanks With the propensity the seahorses have to be afflicted with these bacterial outbreaks you need to play the odds as best one can.