[alphaparrot]

So I've got a blue-green algae (cyanobacteria) outbreak in my 33-gallon southeast asian river tank. All that tank has for algae eaters is nerites (I'd love hillstream loaches, but those seem to be hard to come by atm), which of course don't touch the stuff. My understanding from internet research is that basically nothing eats blue-green algae, and your only solutions are chemical treatment, manual removal, and blackouts. I've been working with the latter two for a few weeks, and it is a slog. I recently moved one of my crypts from the tank to a 5-gallon shrimp/snail tank that needed more plants. That crypt was absolutely beset by blue-green algae, so I figured at best the huge number of shrimp and snails in the 5g would clean it, and at worst they wouldn't, and it would die there instead of in the 33-gallon. Lo and behold, a day after adding it to the 5-gallon, it's totally clean! The shrimp were ALL OVER it.

This is weird, right? Should I be concerned for the digestive health of my shrimp?

And since it *did* happen.... what are the odds other shrimp would do the same? I don't think I can add neocaridina to the 33-gallon; I think the danios in there would bully them to no end, and it's a relatively high-flow tank (~200 gph with a river manifold and spraybar). But amanos, maybe....

 

[alphaparrot]

For completeness, since someone will surely ask:

The snails in the 5g are pond snails (Physella acuta and Radix peregra, near as I can tell), pink ramshorns, and piano snails (Taia naticoides--incidentally, I'm having success breeding those; stay tuned for possible ads in the next year or so). I'm positive the piano snails are not eating the blue-green algae, since I did not at any point see them on the crypt. It's possible the pond snails or ramshorn snails ate it when I wasn't looking, but they didn't swarm to it like the shrimp did.

 

[Student Of The Game]

Is this a 33 long? 48x12x12? What light do you have?

 

[alphaparrot]

It's a 36"x16.5"x12", with a NICREW SkyLED. All my plants are relatively low-light--crypts, dwarf sag, anubias, and jungle val. There's a bit of java fern in there, and there used to be some java moss, but I think it didn't acclimate well to the river environment. I'm fairly certain the source of the BGA outbreak is that a) some of my large stones are close enough to the glass that the nerites can't get in there to scrape the glass, and b) the ceiling lights in the room are bright daylight LEDs--the BGA is mostly on the side of the tank that gets light from the room. I haven't had issues with the ceiling lights in the other tanks in the room, but those tanks are full of shrimp and snails, or they're blackwater, so they basically never have algae issues.