How big is `big enough' frag?


Premium Member
Hi Anthony - looking forward to meeting/hearing you when you come to Madison for the WRS talk in a few weeks.

My Question -

How big is a `big enough' frag to take? I've read your and other books, and I guess I didn't get a clear idea of how big my frags should be.

For example, on a finger leather, I've cut about 1" frags off a
healthy large mother colony. The mother's arms were not really
any longer [otherwise I would have made the frags bigger] ... is
this big enough?

How large is good enough for maximum survivability of the frag? I'd guess the larger the better, but there's only so large I have space for before I want to trim it down ...


Second example .... a Montipora Digitata. I have a nice frag I got that has been growing great - 1-2" [3-4" to start] on a dozen new branches since July 1st. Last night I broke off 2 1" branches from the base so I could move the mother colony over a few inches in my tank.

Is 1" big enough for an SPS like this? I figure once healthy and growing again, I'd want to have it grow 1/2" in my tank before letting it go [at least] and that would be starting to be a decent small size frag then.


All these are on the small side, I know. But I'd love your advice on how smaller frags work/recover ... whether I'm better off leaving them until larger as they'd recover and subsequently grow faster ... or whether it matters a significant amount either way.

Thanks for the advice. If you can't reply ... you can be sure I'll pester you with this question at the end of the month. You can't get away that easy with this one :)

Cheers, Mark

There is no hard and fast rule for size of frags taken... and it is mentioned in passing by species/group in a few places in mt Coral Propagation book (generally on p.379 under Strategic Selection of divisions)...

but the gist of it is that, yes, larger is obviously better. SPS are less demanding than octocorals usually...

one inch long is a fair minimum when possible, three inches is a sound/better frag. With branching digitate species, having at least one forked branch is helpful in case of infection (something can still be salvaged).

There certainly are exceptions... mere slivers of Sarcophyton or 1/8" tips of sps have been known to regularly survive.

Still... towards 3" long will hedge your bets nicely.

Best regards,

Thanks! That's just exactly what I was looking for.

Now I can think up harder questions to ask when you speak in Madison for WRS [devious smile] ... I've been looking forward to that for quite a while now.