General Information: In the
Blastomussa species there are only two species,
Blastomussa merleti and
Blastomussa wellsi. The main difference in these two species is the size of the polyp.
B. wellsi has a much larger polyp much like a mushroom or a ricordia.
B. merleti has a smaller polyp much like a zoanthid. How to best care for these two species and their needs are much the same.
Lighting and Water flow: Blastos differ in lighting needs from colony to colony. This has a lot to do with the conditions in which they were collected from. Some
Blastomussa colonies like medium flow and high light others may like very little flow and very little light. My suggestion with them would be to acclimate them carefully to high light and if they don’t like high light keep them lower in the tank. The only colony of
B. wellsi I own is in medium light and high flow.
Aggressiveness: Blastos are not at all aggressive. They are a species that has very short sweeper tentacles. Obviously something that is a couple centimeters away has the chance of being stung by them but they aren’t going to attack something 2” away.
Hardiness: Both of these species are very hardy once established and acclimated to light and flow. They can also become fast growers.
Feeding: Most of their food comes from the zooanthellae that hosts inside the coral that produces food for the coral through the light. But additional feedings of mysis shrimp or any other type of food small enough to swallow are great for accelerated growth.
Propagation: These may be propagated by cutting through the skeleton. They should heal over fairly quickly.
Blastomussa wellsi 
This a picture of my only colony of Blastos.
Blastomussa merleti 
Hope you all enjoyed this one! Feel free to ask questions, share pictures, and offer suggestions!
Matt