coral

[bignose]

Can coral live in a brackish tank?

[Pufferpunk]

That would be an excellent Q to put to our Mentor, nmonks.

[Pufferpunk]

That would be an excellent Q to put to our Mentor, nmonks.

[nmonks]

The simple answer is that while there certainly are some corals native to mangroves, in practise you can't keep corals in a brackish water tank. For a start, corals need excellent water quality, you're almost certainly going to need live rock and a protein skimmer, and these are most easily used in full marine conditions (though skimmers certainly work at SG 1.010 upwards, and in theory denitrification will take place in live rock at reduced salinities, even if most of the other critters are killed). You're also unlikely to be offered mangrove corals because most collection takes place on coral reefs. Even if you could obtain mangrove-dwelling corals, these tend to be small things like cup corals and plate corals that encrust mangrove roots, and primarily at the seaward end of the mangrove where the salinity is either marine or only very slightly less than fully marine. There aren't any corals (to my knowledge) that tolerate even moderately brackish water, let alone low salinity environments.

There aren't many corals in estuaries because the water in these places tends to be silty, cutting down light and making it difficult for photosynthetic corals to grow. Even non-photosynthetic corals will be at risk of being smothered by the silt, and estuaries tend not to have the clean, rocky surfaces corals favour.

You do sometimes see the European beadlet anemone (Actinia equina) offered as a "brackish water anemone" on eBay and the like. Up to a point it is true that it tolerates less than fully marine conditions, and from personal experience I can confirm it thrives at tropical temperatures. Being small and (usually) bright red it is a nice little thing to add a tank, and if happy it will breed like crazy, essentially being a livebearer that spits out miniature anemones periodically. But it still needs reasonably good water quality, and I wouldn't expect it to do well below SG 1.015, so at best it's a high salinity brackish water resident rather than something for mid- to low-salinity systems.

Cheers, Neale

Can coral live in a brackish tank?