Coral aggression.

For those of you who are just starting out in keeping corals it is important to do a little research before rushing out and buying that cool looking green torch or that beautiful brain coral. When introducing new corals to your tank it is VERY IMPORTANT that you understand both the living requirements and compatibility of that coral species. This post covers one of the topics discussed in a past South East Aquarium Society meeting- Coral Aggression. (http://www.aandtsociety.org.au/)

Corals in the wild are continually competing for space and nutrients. In response to this corals have developed specialised mechanisms to fight for space. Coral species use a mix of specialised sweeper tentacles, mesenterial filaments and toxic compounds to compete with each other. Sweeper tentacles are specialised nonfeeding tentacles that are packed with nematocysts (stinging cells). These tentacles sweep around the edge of the coral stinging anything in its path. This can cause localised tissue damage or death to surrounding corals. Some species have very large sweeper tentacles and this includes hammers, frogspawns, torches, etc.

Mesenterial filaments are stomach components of some stony coral species. The corals expel these mesenterial filaments onto neighboring corals and literally digest the other corals tissue. This is done by many of the brains and slow growing stony corals.

Soft coral species are able to compete with hard corals by producing toxic compounds called terpenoids. The corals release these terpenoid compounds into the water which can inhibit the growth or kill neighboring hard coral species.

With this in mind it is very important to give corals adequate space to grow as well as making sure your coral colonies are stable and will not fall onto each other. As a rule of thumb I would recommend leaving a free space of approx 10cm around sps corals, 20-30 lps corals, and a similar distance around softies although most softies can exist fairly close to each other. Just make sure you do your research and know that you can provide for the coral you wish to buy as well as its compatibility with the species in your tank.

Thanks,
Louis