How to tell if favites/favia/etc are the same species?

[Tired]

I'm upgrading my tank to a larger size, and would like to collect a few favites/favia/etc type corals that I previously haven't had the space for. I know corals of the same species generally don't fight each other, so I'm curious if there's a reliable way to tell if two frags of favia-shaped coral are the same species. Does it come down to examining polyp shape/size/texture/walls/etc and then carefully putting them where, if they do attack each other, they can't kill each other off?

Do the Fascination-type favites all get along well? I love these lil minis, and would like to collect a few species and let them blend together.

Are there favias/etc that will attack each other despite being the same species? I have two psammocoras currently fighting at the edges, and I can't tell if they're different-but-similar species or if they're the same species but still mad about it.

 

[KrisReef]

Certainly can't be helped if they want to. Difficult for id because you need a scope and dead skeleton and a lot better understanding of corallites, sepia, ridges and splines not to mention that external growth characteristics can be wildly different in the same species collected from different locations, microclimates, currents, and distance from the equator.

Jen Veron would tell you, but I'd just get ones you like, glue them next to each other and observe the show. Sometimes they might pleach, what some might say is a graft but the term is known to cause agitation so

 

[encrustingacro]

True favias are never found in the hobby, as those are only from the atlantic, where no stony corals are collected. Most of the favias in the hobby are dipsastraea, with others being favites and coelastrea.
Dipsastraea is usually plocoid, with both intra and extracalicular budding. Some exceptions to this are dipsastraea rosaria (some prism favias), which can be subplocoid. Favites are usually cerioid. Exceptions to this are the ex-phymastrea species (F. colemani, valenciennesi, and magnistellata), and F. rotundata. You can tell the ex-phymastrea species from dipsastrea by their type of corallite formation: ex-phymastreas use mostly extracalicular budding to produce new corallites, while dipsastraeas use both extra and intracalicular budding. F. rotundata has a distinct look that differetiates it from other dipsastraeas and favites. Coelastreas have angular corallites with steep walls and a well developed paliform crown. The most common species in the hobby, C. palauensis, has larger corallites.
It is very hard to tell the difference between species, sometimes to the point that you need genetic analysis to identify them. This is coupled with the fact that corals, once adapted to captivity, can look very different than their wild counterparts. A good starting point for identification is the COTW website; however, note that COTW is unreliable for taxonomic nomenclature. You might need to look up species names in the WoRMS website to find the accepted species name.

 

[Tired]

Okay, so what I'm hearing is that, from a purely hobbyist perspective, they can't really be IDed to species. Not without growing one out enough to cut off and kill a portion of it to examine the skeleton, I suppose.

If two different frags are going to fight, will putting them so close that they touch be guaranteed to provoke them into fighting quickly? Or is there some possibility that they might tolerate each other for a couple months before deciding to sting?

 

[KrisReef]

Okay, so what I'm hearing is that, from a purely hobbyist perspective, they can't really be IDed to species. Not without growing one out enough to cut off and kill a portion of it to examine the skeleton, I suppose.

If two different frags are going to fight, will putting them so close that they touch be guaranteed to provoke them into fighting quickly? Or is there some possibility that they might tolerate each other for a couple months before deciding to sting?

Things that fight over space may just grow together in opposite directions to avoid “fighting” and concentrate on growing bigger (and maybe over) their neighbors. A lot of people grow “enemies” right next to each other in captivity and the war is not that violent. This doesn’t apply to things like space invader pectinia, many lps with sweeper, those always seem to fight.
The encrusting corals you are interested in may be fine as neighbors?