cyanobacteria

[dan182]

I have a freshwater 40ga tan. This purple stuff has started to develop on the walls and a little on a rock (not on the plants yet). Has anyone seen this  purple stuff before? Is this cyanobacteria? I've added Chemiclean but so far there has been no change. I'm going to change the water and do it again. I'm hesitant to use erythromycin because of its affect on beneficial bacterial.  Any thoughts?

Edited July 13, 2021 by dan182

[Rob E.]

I'm fairly certain that this is not cyanobacteria. cyanobacteria has a blue-green color, slimy, sweet earthy smell, and comes off in sheets.  This appears to be more bushy, more like a beard algae.  Is it really stuck on? If you rub it with your finger does it come off easy, or does it feel like coarse hair? Do you have a lot of iron in your water? 

[PineSong]

On 7/13/2021 at 6:33 PM, Rob E. said:

I'm fairly certain that this is not cyanobacteria. cyanobacteria has a blue-green color, slimy, sweet earthy smell, and comes off in sheets. 

I heard Cory say in a video that blue-green algae has a smell, and I was wondering what the smell is--I've had blue green algae in the past, once in a betta bowl and once in a goldfish tank a million years ago. I don't recall smelling anything, so I probably associated the smell with something else at the time if there was one. Today I came home and my kitchen smelled like boiled cabbage and dead rat. I've never boiled cabbage in this house and it seems unlikely there's a dead rodent... do you think that could be the smell of a blue green algae attack coming on?

[Streetwise]

That looks like the color of Cyanobacteria in a marine tank.

[Rob E.]

@Streetwise That is interesting! I know nothing about marine tanks, so I had to look it up and it does indeed look like cyanobacteria in a salt water tank.

[Guppysnail]

Thorough cleaning vac Reduce light or black out for a few days then water change. Repeat until gone Use a phosphate elimination media for a week or so if it is Cyanobacteria.  Plants may suffer a bit but is easier on fish than cycle disruption from erythromycin 

[Rob E.]

@PineSong The smell that you are describing sounds too strong to be cyanobacteria, my first thought is that maybe there is some old fish food stuck to the tank rim or lid, or a maybe a dead snail.  

I have this tank in my kitchen that I've been fighting cyanobacteria for years. I've gotten rid of it multiple times using antibiotics and blackouts, but it always comes back.  I finally decided to move the fish about a month ago, but haven't had time to tear down the tank.  As bad as it is, I can't smell anything from it right now.  I normally only smell it if I'm trying to manually remove it.

[PineSong]

Thanks. I only have one snail and he's alive, and I'm not missing any fish. Maybe it's all the plant matter that has been going down my drain recently with water changes, or maybe there is a dead squirrel in the attic 😞 Your tank looks like a Halloween park for fish--very creepy! So weird how it keeps popping up for you. I was watching some Doug Grey guppy videos and he had it in one tank only in a whole row of tanks--made me feel better about my past episode. I blacked it out in my betta bowl but I'd bet that it will be back since I didn't tear the whole setup down.

[Rob E.]

lol, my tank is very creepy! It use to look really nice, had it aquascaped with nano fish.  Eventually I made it into a pea puffer tank and it became more difficult to manage the algae and cyanobacteria.  The pea puffers got a bigger tank now, with auto water change.  I really should have torn it down by now, but I'm oddly fascinated by how terrible it looks.

[NanoNano]

On 7/27/2021 at 5:18 PM, PineSong said:

I heard Cory say in a video that blue-green algae has a smell, and I was wondering what the smell is

I think there's a couple of different strains and the smell can depend on things like what it's feeding off of...The stuff that I've had has a smell that reminds me kind of sort of like sliced cucumber.

[PineSong]

Sliced cucumber sounds much nicer than boiled cabbage rat!

[dan182]

Just as a follow up. I used Chemiclean and it did the job.  Thanks all for your input!!!