cyanobacteria-toxins-ich

[boxfishpooalot]

Hi Randy,

To my understanding(poor one) cyanobacteria can produce toxins that can harm people, and their liver.Perhaps fish also.

By my experience, I find that cyanobacteria only will grow in my tank when I notice some ditritus build up in the sump. It only grows when ditritus is present. Upon removal of the ditritus the cyanobacteria dies back, despite high phophate levels indefinitely(tap water)

Also, to my surprise, the fish seem effected by the presence of cyanobacteria or the ditritus. Perhaps a combination of both.

The funny thing is, that I find that some fish contract ich easily with cyano and the dirt present in large numbers. When the cyano dies back, and the dirts been syphoned out ich goes away. STRANGE! I have done this repeadly.

Do you think cyanobacteria could weaken fish to be more suceptible to parasitic infection? Or organic toxins from the ditritus piles effect them some way? I wish there was a way to find out.

Thanks Box :)

[Randy Holmes-Farley]

I do not know whether toxins from cyano normally play a role in fish stress. It is certainly possible, but with skimming and carbon use, I do not know if it is a significant factor.

I do not think that detritus itself releases what I would call toxins.

[boxfishpooalot]

taken from http://www.skepticalaquarist.com/docs/algae/cyano.shtml

"Be prepared for the massive cyanobacterial die-off. Dying cyanobacteria can release toxins that will stress your fish and all the other organisms in the tank and could be deadly. Cyanobacterial toxins affect the neural system and damage the liver. Liver damage will not be evident perhaps, until a victim suffers symptoms of "dropsy" long afterwards. Rinse out the filter media each day. Manually collect as much of the cyanobacterial sheets as you can in a brine-shrimp net. After 48 hours, do a 40% water change and repeat the erythromycin dosage. On the fourth day, siphon again carefully and do another 40% water change."

This was from a treatment with erythromyacin to kill the cyanobacteria. Also I think it was done on a freshwater tank?

What is "dropsy"

Also, "Cyanobacterial toxins affect the neural system and damage the liver" what would theese systems be responsible for? Liver is an obvious one, but the neural system?

[MiddletonMark]

But wouldn't cyano also only appear when there's nutrient issues in the tank ... and to a degree, these nutrients/water-quality-issues can also affect the fish?

IMO, it's hard, in an aquaria, to separate the poor water quality from the cyano ... and thus link one vs. the other.

JMO.

[Randy Holmes-Farley]

Rapidly killing off bacteria can certainly lead to toxins in the water. I do not know anything about dropsy. The neural system means the central nervous system, including the brain. Nerve impulses, feeling and other senses, controlling muscles, etc.