MIN 75 gallon tank with rock. All Pygmy Angels offered here I consider to be "reef safe". I've had them with clams & haven't seen any bad behaviors in my soft & LPS coral tanks. They are easy keepers when fed a good diet & can be housed together when introduced properly. All Angels need a MIN 75 gallon+ tank with plenty of rock. Angel fish are constant swimmers & need the space! Do NOT put them in tanks smaller than a 75g! In my 20+ years experience with them I've found we can have multiple Pygmy Angels in a 75g+ aquarium. The best success to have multiple different Pygmy Angels is to introduce them at the same time & better yet, with different body styles (LB = Long Body or SB = Short Body). Pygmy Angels are avid swimmers & are always searching their tank for a tasty morsel so again, live rock is needed as well as a min tank size of 75 gallons. Worthy of note ... I have a Flame Angel & a Lemonpeel Angel in my 220g #1 tank ... both 14 years as of 2019!