Can algae kill fish?

[csababubbles]

In one of my fowlr tanks I have a piece of live rock that has a massive amount of feather caulpera growing on it. I think it looks very nice and would like to keep it and not trim it back. For some reason my Idol like to chew on it too, which I have never heard of but he seems to enjoy it. Anyways, is there any possibility that this macro algae can kill fish either through digestion or through releasing spores and such that would suffocate the fish?

 

[Damsel13]

I know very little except that some algae go sexual. I am sure someone with more knowledge will answer.

 

[leebca]

Idols are Tangs, as I have previously written. They eat a lot of algae. They were classified into the Tang family for many reasons, this being one.

Some wild algae are not suitable for marine fish eating. In the wild, the fish knows best. In the captive environment, faced with no other source of algae, our marine fishes can and do eat the 'wrong kinds.' Some do nothing more than cause blockage of the intestinal track, others may impart a mild toxin.

As far as which are which, I don't know. If the fish has been eating it without any noticeable adverse affects, it is probably okay. Just be sure to offer sheet macro sea algae regularly so that wild algae isn't its sole source of vegetable matter.

 

[csababubbles]

lee, two questions:

what about when the algae go sexual and start releasing their sexual goodness into the water, i've seen some scary pictures of white tanks. does this usually kill the fish?

second, are seaweed flakes (for example Julian Sprung's Seaveggies) better then nori? i recall you saying one time nori was not your favorite herbivore food and there are much better options.

 

[leebca]

There is many opinions about algae. One of the most common opinions is how horrible it is when (and if) it goes sexual.

There is no doubt that an algae going sexual will create quite an upset to the water quality. That may lead to fish losses. But there is one thing I don't totally believe about this. . .That the algae has to go sexual.

Some algae can do this (but, will it?). If the algae in question is one that can go asexual, the hobbyist who still wants to keep it has to do a couple of things.

1. Be on the lookout for when it goes sexual and take immediate action;

2. Try to prevent it from going sexual.

Few people describe what 1. looks like, but I have seen it and know what to watch for. I'll share this with you. If you are at all familiar with corn you may know that when the corn kernels/cobs are developing all the stored sugar in the plant goes into that reproduction phase. The plant turns brown. But, the plant is still alive. Its energy goes into the corn cob, from the leaves and stalk.

A similar signal is sent by macro algae before it goes sexual. The tips start turning brown AND/OR the leaves start going clear. THAT'S when the hobbyist has to intervene. Rip it out, and leave just a few stems and green leaves to restart the next generation.

As to 2. just keep it cropped. A plant that has an abundance of nutrients and gets old is prime for going sexual. Don't let it get old. I keep mine cropped back and, at the same time, watch for 1. In my own experience, after I figured out 2. I have not had my algae go sexual for over 7 years.

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What I don't care for is nori -- the human food. I prefer actual sheets of raw, chemical-free, natural macro algae. This is the first choice. Next can be actual flakes of macro algae. If grown macro algae (available sometimes on the Internet) is available and quarantined, that is an excellent choice. So is some harvested by hobbyists living in certain areas where ocean algae is unpolluted. Beyond these, Spirulina in prepared foods is great. After this, I can't think of anything.