Bga Toxicity To Fish...

[lljdma06]

I was reading a thread in bettas today...

http/www.fishforums.net/index.php?/topic/362680-seriously-ill-betta-plz-help/

I feel very bad for the OP in that thread, as he was keeping the fish in a filtered, heated 15l tank. But I couldn't help but notice the cyanobacteria that covered the substrate near the fish. OP mentioned a severe BGA problem.

I've been reading some and supposedly there is a toxicity to fish. I know fish won't eat it, but I wonder if it is indeed toxic and could potentially cause death or disease, or contribute in some secondary fashion. I'm no algae expert, lol, cause I don't get any...

Anybody with thoughts? I'd like some confirmation for or against, before I go to that section with these thoughts.

Thanks,

Liz

 

[StandbySetting]

Cyanobacteria can produce toxins called cyanotoxins, all of these fall under one of the following categories: neurotoxins, hepatotoxins, cytotoxins, and endotoxins, all of which if ingested by aquatic organisms will cause problems.

I studied algae as part of my A-level Biology course and found this information, I've just pulled it from my coursework.

 

[lljdma06]

So this could indeed contribute to disease if the the fish was kept under such conditions for an extended period of time?

This gels, by the way, with what I read.

 

[StandbySetting]

I guess it's possible, as it is toxic to humans also, some of the neurotoxins can account for Motor Neurone disease from what I've read, we're closely related to fish genetically, so it must have some ill effect on them even though it hasn't been widely studied.

 

[StandbySetting]

Anabaena (Cyanobacteria) is toxic to Carassius auratus (Goldfish) when administered orally or intraperi-toneally (Into a cavity) On the other hand, if the animals were only immersed in the toxic water they were not affected, meaning that the toxins were not readily absorbed through the gills.

Taken from: Carmichael et al . (1975)

The bits in brackets I've simplified for those not familiar with the terms, and this would only be relevant to freshwater fish, whereby osmoregulation occurs through ion uptake through the gills and through the dermis of the fish, the above could not be applied to Saltwater as they ingest the water they live in as part of osmoregulation.

 

[ian]

Theres not a lot of evidence out there that it is harmful to aquatic life (just had a look through Cinahl), there is evidence that it's harmful for dogs, but there is different strains of BGA and only certain ones are harmful. That came from a vet friend, who also went on to say that not all strains are actually toxic to either aquatic life or animals, the toxic strain is still quite rare. I'm sure the aquarium variants aren't toxic. But i'm not BGA expert. Where Tom Barr when you need him!

 

[coldcazzie]

Anabaena (Cyanobacteria) is toxic to Carassius auratus (Goldfish) when administered orally or intraperi-toneally (Into a cavity) On the other hand, if the animals were only immersed in the toxic water they were not affected, meaning that the toxins were not readily absorbed through the gills.

Taken from: Carmichael et al . (1975)

The bits in brackets I've simplified for those not familiar with the terms, and this would only be relevant to freshwater fish, whereby osmoregulation occurs through ion uptake through the gills and through the dermis of the fish, the above could not be applied to Saltwater as they ingest the water they live in as part of osmoregulation.

The logical conclusion being from this that if the betta had made a habit of eating or mouthing the BGA then that may, theoretically, have been a contributory factor? I did microorganisms as part of my Bio Alevel but it didn't cover this...

 

[StandbySetting]

It's possible, but the Anabaena species stated was the flos-aquae strain, as Ianho stated, it depends on the strain that is present in the tank.

 

[nurglespuss]

Hi there,

With cyano bacteria (we ecologists/biologists etc. would love the name blue green algae to fade into history!) it often depends on concentration of emitted toxins.

You may have heard of the 'red tides' that occur fairly regularly with huge blooms of cyanobacteria. Most often its just one species, but on many occasions the make up can be complex.

In the confined area of an aquarium, there is really no where for these toxins, if released to go, and so concentrations can reach toxic levels fairly rapidly. Equally though, many species of cyanobacteria emit no such toxins and either retain them as part of their physical structure or convert them to other resources.

The key to controlling it is preventing access to nutrients and light (no surprises there).

Usually, it can be left to run its course, and is often out competed by more usually encountered algae, fungi or bacteria.

 

[lljdma06]

This is interesting, so we'd have to know the exact strain of cyano then? Hmmm...

Liz

 

[RadaR]

You may have heard of the 'red tides' that occur fairly regularly with huge blooms of cyanobacteria.

Dinoflagellates.

 

[nurglespuss]

yes, you get tides of dinoflagellates too, sometimes they are mixed...

dinoflagellate tide

Lyngbya (cyanobacteria) can form toxic floating mats after badweathe.

I think you are reffering to the Red sea (in which case its dinoflagellates and not cyano bacteria that cuase the deadly tides)