White Mouth On Diamond Tetras

20 gallon long
Aquaclear 50 filter
Ammonia: 0
Nitrites: 0
Nitrates: 5
PH: 7.2
Temperature: 77F
10 neon tetras (new)
9 diamond tetras
9 salt and pepper cories (c. habrosus)

I've had the diamond tetras for a month or two now? I just got the neons last week. I have an algae bloom I'm dealing with, so I've kept the lights off most of the time and do water changes every other day. I use prime, excel, and added pristine with the new neons.

I googled "diamond tetra white mouth" and was led to a lot of information on Columnaris/cotton mouth and how common it is in neons especially but all tetras. I admittedly did not quarantine my new neons, but I see no sign of white mouths on any of the neons.

The thing is, it doesn't look like a bump or growth. It looks like their mouths turned white. It's only two males only. They still eat fine, they are active, they shine nicely, basically they seem normal and healthy and just have a white mouth.

I feed regular Tetramin tropical flakes, NLS pellets (tiny ones mostly for the cories and neons but the diamonds eat them too), sinking algae pellets for the cories, and sometimes frozen bloodworms or brine shrimp. I was thinking about getting some krill after seeing Rachel O'Leary's video of how all fish love it, but I haven't yet. I don't feed all of these at the same time, of course, and I've only been feeding every other day because of the alagae bloom. Sometimes the diamonds pick up the alagae pellet and swim away with it, but I've never noticed a particular one doing it or the ones with the white mouth.

Any ideas? I'm open to treating it as columnaris, but since it's not a growth, I'm not sure that's what it is and don't want to do a bad or wrong treatment. Thanks!

 

I'm sorry, I don't know what that is or how to treat it.

I did want to mention that you have stocking issues, if you'd like to discuss them.

 

It might be an injury and resulting scar tissue, e.g. from bumping into something.

I have the same on 3/10 of my harlequin rasboras. I noticed it when I first got them and also feared it was columnaris. 2-3 months down the line, the fish in question have grown well, are brightly coloured and appear healthy, active, feed well etc. It hasn't spread to any of the others and there have been no deaths. So I just don't believe it's an infection. The white areas have reduced to tiny bumps but are still visible when I look closely. I also Googled a lot and this is what I found.

 

I'm sorry, I don't know what that is or how to treat it.

I did want to mention that you have stocking issues, if you'd like to discuss them.

I'm willing to hear what you think they are

 

It might be an injury and resulting scar tissue, e.g. from bumping into something.

I have the same on 3/10 of my harlequin rasboras. I noticed it when I first got them and also feared it was columnaris. 2-3 months down the line, the fish in question have grown well, are brightly coloured and appear healthy, active, feed well etc. It hasn't spread to any of the others and there have been no deaths. So I just don't believe it's an infection. The white areas have reduced to tiny bumps but are still visible when I look closely. I also Googled a lot and this is what I found.

That's very helpful! I ordered some stuff listed in the sticky post about columnaris but I'll keep an eye on them for a couple days before it gets here

 

I think diamonds will get too big and active for a 20 gal long. They get pretty big as adults, actually. They're also not temperature compatible with neons and there's not much overlap with the cories; both schools of tetras together overstock the tank. I'd rehome the diamond tetras or move them to another tank.

 

I think diamonds will get too big and active for a 20 gal long. They get pretty big as adults, actually. They're also not temperature compatible with neons and there's not much overlap with the cories; both schools of tetras together overstock the tank. I'd rehome the diamond tetras or move them to another tank.

According to everything I've read, diamonds need a minimum of 20 gallons, I saw one site even say 15. And from what I've read, diamonds need temperatures 72-82 and neons 68-78 so as long as I keep it within the 72-78 range it seems like I should be fine.

 

Aqadvisor isn't accurate. Use Seriously Fish, Fishbase, and Planet Catfish for temperature requirements. You also don't want to keep fish at the extreme ends of their temp ranges, making diamond tetras incompatible with neons and not much overlap with these cories. So no, anywhere in that range is not fine.

Diamond tetra get 2.5" long without their fins, and they are thick fish. I really don't think you have room for both those and neons in such a short tank.

 

If it were me, I would treat it as columnaris.

Just wanted to throw out there that cories don't digest algae wafers well and there's little to no nutrition in them. I'd suggest switching to shrimp pellets and bottom feeder wafers.

 

Aqadvisor isn't accurate. Use Seriously Fish, Fishbase, and Planet Catfish for temperature requirements. You also don't want to keep fish at the extreme ends of their temp ranges, making diamond tetras incompatible with neons and not much overlap with these cories. So no, anywhere in that range is not fine.

Diamond tetra get 2.5" long without their fins, and they are thick fish. I really don't think you have room for both those and neons in such a short tank.

Seriously Fish says 20 gallons is big enough, fishlore's info page says 20 gallons is big enough, liveaquaria says 10 gallons, animal-world says 15 gallons, fishbase says 31 inches and mine is 30, so I guess there's one site that says something different, but that's not much. I see and understand that you are highly respected here and people ask you for stocking advice, but I just haven't found anyone else that says I can't keep them together. In fact, I found a couple sites that recommend diamond tetras as tank mates for neons. They are not those same big name sites, I think they appear to be lfs sites, so I don't take that as gospel, but I just did a lot of searching and couldn't find anyone else saying I can't keep them together.

If it were me, I would treat it as columnaris.

Just wanted to throw out there that cories don't digest well and there's little to no nutrition in them. I'd suggest switching to and bottom feeder wafers.

Thank you! I actually looked at the bag and they are HikarI tropical sinking wafers for cories and have krill and other things in them. Is that okay or is there something else I should feed them? I don't give them often because they can't eat them in 30 seconds - 1 minute and I don't want food sitting in the tank, usually they eat flakes that make their way down or the NLS pellets that are tiny enough for their mouths.

I ordered some of the antibiotics listed in the stickied thread on columnaris, and I read that it's ok to put them in even if they don't have it, so I'll still try that and see what happens.

 

HikarI sinking wafers are perfect! They're what I usually recommend and use with my own cories. You can add some variety too though - frozen brine shrimp or bloodworms, and shrimp pellets/wafers. I've never followed the time limit for cories since they're slow eaters - as long as it's gone within a few hours I don't take it out. I would give them a few wafers a day since they should be fed more than just the leftovers from the other fish.

 

Again, many sites are not accurate. LiveAquaria and Animal World often give inappropriate info.

SF gives a 20 gal tank, yes, but SF isn't always accurate either. A large schooler like this should be in a 30" long tank. And yes, you could keep them in a 20 gal long - it'll be a bit tight, but it won't kill the fish. However, you have two other schools in there - in a tank that's shorter than 12" tall with substrate, it's really a cramped stocking.

And the temp incompatibilities exist. You can ignore them, but that doesn't mean they're not there.

You can do whatever you want with your stocking; you don't have to listen to me. But I do recommend conservative stocking options that I think would be best for the fish, even if it's not better for the owner.

 

Again, many sites are not accurate. LiveAquaria and Animal World often give inappropriate info.

SF gives a 20 gal tank, yes, but SF isn't always accurate either. A large schooler like this should be in a 30" long tank. And yes, you could keep them in a 20 gal long - it'll be a bit tight, but it won't kill the fish. However, you have two other schools in there - in a tank that's shorter than 12" tall with substrate, it's really a cramped stocking.

And the temp incompatibilities exist. You can ignore them, but that doesn't mean they're not there.

I'm not trying to be rude, but where is accurate then? No where on the internet except you?

 

I am far from an expert, but I do mostly very conservatively stock.

Have you seen adult diamond tetra? They're pretty large; having a 20 gal long myself, I wouldn't keep a large school of them in a 20 gal long with two other schools. It'll be cramped, that's all I'm saying. I would think they fish would prefer more swimming room.

The temperature incompatibility information comes from the most reputable sources we find online.