What is killing my Harlequin Rasbora?!

[Vladka]

I had 5 for a long time and added 7 more and now, within 3 months I only have 3 left! One of the ones left all has a small white spot (fungus maybe?) on the mouth and the rest are otherwise acting normal. When one dies there were a lot of flat white worms crawling over and around it and a chunk was taken out of it, can’t tell if they were coming from inside or just eating it. These might be planaria but I am not sure, I have medicine to treat planaria just worried about shrimp and snails (the one I have is deff okay for shrimp though) I see the points on the head but not the eyes and they’re small and flat and white but there’s rather a lot of them.

Also battling green hair algae and some black beard

Cardinal tetras and one neon tetra seem to be fine.
29 gal planted tank

 

[goatnad]

They do look like planaria. The white stuff of the mouth is probably cottonmouth which is a form of columnaris. For the algae issue try slightly larger water changes or more frequent changes. Also try to reduce the intensity of your light or how long they are on.

 

[Vladka]

They do look like planaria. The white stuff of the mouth is probably cottonmouth which is a form of columnaris. For the algae issue try slightly larger water changes or more frequent changes. Also try to reduce the intensity of your light or how long they are on.

I’ll do the planaria treatment, I can’t find much on cottonmouth but not sure that’s what’s killing them? Should I cull? I don’t want the cardinals to suffer at all...
the algae is terrible I stopped feet’s and reduced lights and kept co2 and it’s still there! I will admit I don’t do water changes much because the parameters are perfect and I just add RO water when needed. I’ll try doing weekly for a little bit but refilling with RO is annoying so I don’t like having to use more water than needed. Here’s a better pic of his mouth:

 

[goatnad]

That does look to be cottonmouth. I know changing water can be a pain but all the issues you are having have one thing in common. Not enough cleaning of the tank. Planeria are caused by poor cleaning which can mean poor water quality. This will lead to your fish dying and others being susceptible to infections like cottonmouth. Don't give up hope on the cardinals. You just gotta give them the right conditions. Do you have any test results to link? Ammonia, nitrites, nitrates, TDs, pH, GH, kh. Anything that can help better understand your tank.

Also meant to say stop worrying about precise parameters and instead watch what the tank is doing and use those supposed recommended parameters as guidelines. If fish are dying in perfect parameters then they aren't perfect after all

 

[King Fisher]

It looks to be a fungal infection. There's meds out there to treat that but I would remove him to a quarantine tank then treat.

As goat stated......testing your water and having an idea what you have going on helps. Id add that you should also test for phosphates because of your algae issues.

 

[Vladka]

Sure! I just checked my parameters and here they are:
Ph: 7.6-7.8 (borderline)
Ammonia: 0
Nitrite: 0
Nitrate: 0
Always trying to get those nitrates up but haven’t been dosing ferts since I’m battling the hair algae.

Is it low phosphates that cause algae? I’ll have to see if I can order a test for that.

I used to have gh and kh kits but they’re expired now and results never changed. They were around 10-11 before because our tap water is hard, which is why I use RO for this planted tank specifically.
I do lots of water changes on all my other tanks, I’m not just being lazy [emoji28]

Would it be best to quarantine all the rasbora or just the one with the visible cottonmouth?

 

[Vladka]

Just pulled out my “no-planaria” bag and am feeling apprehensive about starting.
Definitely going to be taking out the nerite snails for treatment but I’m seeing people say that they can’t put snails back in for months after?! Also have tons of rams horn and mts in there and not really into killing all of them :/
From what I can tell the cardinals and ottos should be okay as long as I do it right

 

[goatnad]

Just pulled out my “no-planaria” bag and am feeling apprehensive about starting.
Definitely going to be taking out the nerite snails for treatment but I’m seeing people say that they can’t put snails back in for months after?! Also have tons of rams horn and mts in there and not really into killing all of them :/
From what I can tell the cardinals and ottos should be okay as long as I do it right

Planeria are said to come from poorly cleaned tanks or tanks with overfeeding. Maybe one of these are your issue?

 

[Vladka]

Planeria are said to come from poorly cleaned tanks or tanks with overfeeding. Maybe one of these are your issue?

Well in this tank I do not vacuum the substrate or surface since it’s heavily planted, I do occasional water changes (maybe once a month or so) but mostly I just top off with RO.
I try not to overfeed but I did get a little pellet happy in the last month.

 

[Vladka]

Update: now one of the cardinals is showing something strange, looks like 2 sacs under chin, one has a string/worm looking thing inside.
I’ve never seen this before, and am trying to decide if quarantine would be best in a 1/2 gallon tank with under gravel vac or in my 10 gal shrimp tank. Rasbora needs to go somewhere too and I’d rather not medicate this shrimp tank.