Freshwater coralline algae

[Roachant]

Hi all, 

just thought I’d share something, this is a spot of algae on one of my freshwater tanks that has been there for years. I never got rid of it all because I kind of like it, it reminds me of coralline algae. Well as it turns out it MAY be freshwater coralline because it’s hard and crusty and grows like it with the whitish edge all around it. That, and the recent discovery of freshwater coralline makes me wonder. I tried to remove another spot to see what it’s like and it only comes off with a razor.

 

Not the best pic sorry, I’ll try to get a better one if you want me too. The alk is high in this tank so I wonder if that’s why it’s growing in there.

 

[dandelion]

Scrape up a little bit and put it under a microscope. 

[RayWhisperer]

Interesting. I had never heard of anything like this until now. To be honest, I kinda doubted your statement about it being found in FW too. Not a knock on you, I just see a lot of people misinterpret something they read or saw, then talk about it from their flawed recollection. 

 

In my quick reading, the only known FW coralline algae is found in only one river in Croatia. So, you being in Canada, I have my doubts. That is, unless you are keeping snails collected from that river in Croatia. I think the likelihood of another FW coralline algae going undiscovered in an area like Canada is pretty slim. Not impossible, but pretty slim. 

 

Morphologically, your example looks very different from the species that grows in Croatia. Examples of those specimens are below. 

 

Now, on to another possibility. And bear with me, as this is just a guess here. I’m assuming by the CC sand, as well as your comment about the high alkalinity, that this is an African cichlid tank. Do you by chance use some marine salt to boost the Ph and alkalinity of your water? If so, I would guess it’s coralline algae, possibly from your saltwater tank. As many species of coralline can survive in brackish, marine, or even hypersaline environments. There are also many species of coralline found in brackish waters only.

 

Beyond that, I have no idea what you have. It sure looks like coralline in your picture. A bit thin, perhaps, but it does look like it. I’ve never seen anything like it, and I bred Africans for years. Perhaps someone who knows more about FW algae’s can comment. I don’t know much of anything about them beyond the few common ones.

[Roachant]

No worries, believe me I thought I was crazy as well until I saw that same article.

It does appear a bit thinner than regular coralline you’re right, but I can’t shake the fact that it doesn’t appear to be anything else. 

Oh the sand is play sand, it only looks really white because of the lighting.

i currently am keeping barbs in the tank, before it was a North American sunfish tank and before that I had Razorback musk turtles in it. And before that I had a community tank full of fish, inverts and plants. That’s when I first noticed the spot which was tiny back then. I never had saltwater in this tank.

I think I’ll get some scrapings and look under a microscope like dandelion said, and see what it looks like.

[Clown79]

4 hours ago, Roachant said:

No worries, believe me I thought I was crazy as well until I saw that same article.

It does appear a bit thinner than regular coralline you’re right, but I can’t shake the fact that it doesn’t appear to be anything else. 

Oh the sand is play sand, it only looks really white because of the lighting.

i currently am keeping barbs in the tank, before it was a North American sunfish tank and before that I had Razorback musk turtles in it. And before that I had a community tank full of fish, inverts and plants. That’s when I first noticed the spot which was tiny back then. I never had saltwater in this tank.

I think I’ll get some scrapings and look under a microscope like dandelion said, and see what it looks like.

What's the ph of the water?

[Roachant]

Just now, Clown79 said:

What's the ph of the water?

It’s at 7.8.

 

i have an update, I asked a friend about it this morning and he said he has it in his tank too, it starts at the substrate and eventually grows all over. He said it comes from lack of nitrates in the water and that it’s just a form of red algae and not a type of coralline. He also asked why it took me so long to ask about it hehe.

Bummer. I still like it it though and will keep it around 😉.

 

[oubliette]

I have the same red spots in two fresh tanks. Both have a substrate of aragonite and aquarium soil for plants. What I believe started the red spots at first was when I accidentally dropped a small piece of live rock into it from my salt tank right beside it. The spots started where that bit of rock fell against the front glass. I never bothered to remove it. Few months later there were red spots. I really don't know what to make of it beyond speculations. It hasn't presented any issues that I'm aware of and it looks interesting so I've just left it 

[SantaMonica]

Maybe the chemistry near/around the rock give the proper conditions for growth only there.