Coral Competition

Coral Toxicity to Fish

Coral Toxicity To Fish These experiments involved the testing of 68 coral species from the Great Barrier Reef, in which coral tissue was macerated in a blender and added to containers housing fish specimens. Overall, 52% of the corals studied were judged to be toxic. Rating % of Corals Tested Fish Mortality "Very Toxic" 15% 100% within 90 min. "Toxic" 20% 83% within 12 Hrs "Harmful" 17% 67% within 12 Hrs "Nontoxic" 48% 48% within 24 Hrs * *Test subjects were wild freshwater Mosquito Fish (Gambusia affinis), which tended to show high mortality when confined for 24 hours, and factors other than coral toxicity are assumed to have affected those in the "nontoxic" group. (Coll, LaBarre, Sammaarco, Williams, and Bakus, 1982)

Energetic-physiological Competition

Each battle in the war for reef turf ends in one of four ways:

1. The losing coral is killed or overgrown by the dominant coral.
2. The losing coral is killed by algae overgrowth or disease.
3. In a stand-off with neither coral winning.
4. The result of the battle is reversed over time.

Dilution

With all of these corals emitting all of these toxins, how can there be any corals left alive in the ocean? Simple: Dilution. The ocean is so big that the emitted toxins are spread over a very large area, diminishing their effectiveness. The corals' defense mechanisms and ability to heal, grow and reproduce are also essential for survival.

Unfortunately, due to their size, most aquariums do not have the ability to dilute the toxins as well as the oceans. Whatever toxins that are emitted in an aquarium circulate in the water currents until they land and stick to something (i.e. another coral, a fish). The smaller the aquarium, the more concentrated the toxins will become. See 1 to 15 Gallon Reef Tank Photos to view successful mini or nano reef tanks.

So how do your rid your aquarium of these wandering toxins? Activated carbon and ion exchange resins work well in removing a great number of these substances. One would think that foam fractionation (skimming) would remove them also, but the level of effectiveness of this method has yet to be established.

If you have all of these toxins flying around an aquarium, poisoning everything in sight, how do you possibly maintain healthy corals in an aquarium? To begin with, be aware of which corals have the greatest potential for emitting toxins.

Ichthyotoxicity of Some Soft Corals Group Toxic Species Nontoxic Species Alcyoniida 58 20 Loboohytum ssp.* 9 1 Sarcpphyton spp.* 13 2 Cladiella ssp. 8 1 Sinularia ssp.* 28 15 Alcyonium ssp. 0 1 Nephtheidae Lemnalia ssp.* 9 1 Nepththea ssp. 12 7 Dendronephthya ssp. 4 11 Capnella ssp. 0 9 Xeniidae Xenia ssp. 6 1 Cespitularia ssp.* 3 4 Efflatounaria ssp. 4 6 Anthelia ssp. 1 1 *denotes a genus with some very toxic species (after Sammarco and Coll, 1987)

Coral Competition - Turf Wars in Coral Reef Tanks
Coral Competition - Coral Toxicity To Fish
Coral Competition - Signs of Coral Competition