Tetras Dying- Is This Fin Rot?

10G tank
Heated to 79
Nitrogen cycle components all normal
3 Cory cats
(Had) 5 red serpae tetras
(Had) 1 male red swordtail

So earlier in the week I noticed my swordtail had cotton around his mouth. Later that day I bought E. M. Erythromycin and treated the tank. Swordtail died the next day. I continued with the treatment Incase the rest of tank was infected. 2 days later I did the 25% water change as the instructions say. Use prime to treat water (this was last night)

This morning 2 of my red serpae tetras just died and I have no idea why. I see some little white spots on a couple fish but not more than a few. Here is a photo of one of the dead tetras— does this look like fin rot?

 

That doesn't look like finrot to me. Finrot usually doesn't kill fish anyway unless it is very severe. The ripped fins is probably just what the other fish did after it died.

 

you tank has a fungus, its overstocked badly, it could be fin rot or nipping.

 

10G tank
Heated to 79
Nitrogen cycle components all normal
3 Cory cats
(Had) 5 red serpae tetras
(Had) 1 male red swordtail

So earlier in the week I noticed my swordtail had cotton around his mouth. Later that day I bought E. M. Erythromycin and treated the tank. Swordtail died the next day. I continued with the treatment Incase the rest of tank was infected. 2 days later I did the 25% water change as the instructions say. Use prime to treat water (this was last night)

This morning 2 of my red serpae tetras just died and I have no idea why. I see some little white spots on a couple fish but not more than a few. Here is a photo of one of the dead tetras— does this look like fin rot?

I am sorry that you are having trouble with your fish! I’m not really good with diseases and stuff but I do know that it might help another member if we have the exact parameters. Also, most cories really need a thirty gallon and in schools of 6 and more. I hope this helps!

 

It looks like little nip marks... possibly fin rot...I don’t know how bad your swordtail was but before adding meds and all that harsh stuff you should always quarantine and monitor the sick fish first... and then monitor the rest of the tank.. serpae’s are known to be fin nippers...
how long did you have them before all of this? Like were any of these fish new?
Also did you notice the dead fish right away?
Cory’s can be bad for eating a dead fish... possible you didn’t notice them right away and the cories had started eating them?
I have had a fish die overnight and my cories has it half eaten and buried by morning...

 

So as far as the tank being over-stocked. All this fish are still small and if the rule for 1 in of fish per gallon applies then I am right below 10.

For the parameters-
Ammonia stays between 0-0.25 ppm
Nitrite is 0 ppm
Nitrate usually around the 5 ppm mark

In terms of fish- I had just bought two serpae tetras a few days prior to the sword tail showing cotton mouth and dying. Then two tetras had died. I’m now showing light signs of Ick so I increased the tank to 82 degrees and added a tablespoon and a half of aquarium salt. Things seem to be normalizing again.

 

So as far as the tank being over-stocked. All this fish are still small and if the rule for 1 in of fish per gallon applies then I am right below 10.

For the parameters-
Ammonia stays between 0-0.25 ppm
Nitrite is 0 ppm
Nitrate usually around the 5 ppm mark

In terms of fish- I had just bought two serpae tetras a few days prior to the sword tail showing cotton mouth and dying. Then two tetras had died. I’m now showing light signs of Ick so I increased the tank to 82 degrees and added a tablespoon and a half of aquarium salt. Things seem to be normalizing again.

glad to hear the disease is under control, sorry about you fish, the inch per gallon is not true pet stores say that so you can buy more of there fish over and over again. corydoras don't do well in a 10G especially 3, you should either get rid of 1, all, or get a larger tank. The aquarium salt can and will kill the cory cats or make them sick so do a %50 water change ASAP and don't use it again. You can use an ick cure but daily water changes and heat should kill all the Ick. are there any other fish in the tank right now? also what kind of Corydoras are they?

 

So as far as the tank being over-stocked. All this fish are still small and if the rule for 1 in of fish per gallon applies then I am right below 10.

For the parameters-
Ammonia stays between 0-0.25 ppm
Nitrite is 0 ppm
Nitrate usually around the 5 ppm mark

In terms of fish- I had just bought two serpae tetras a few days prior to the sword tail showing cotton mouth and dying. Then two tetras had died. I’m now showing light signs of Ick so I increased the tank to 82 degrees and added a tablespoon and a half of aquarium salt. Things seem to be normalizing again.

Yes please don’t EVER listen to the inch per gallon rule there are waaaay too many flaws with it... that’s just a very very basic approximation that doesn’t take into account for the bioload of each fish and many many other factors... like swimming space... some fish need a ton of wide open swimming space and others need barely any... Also when you buy your fish you need to account for what they are going to be as adults... not when you buy them...
A very easy and fast way to treat ich is a salt bath or dip... it will literally knock the spores right off the fish (instead of adding it to the tank this method is much more effective)
Your serape tetras a known fin nippers especially when in groups of 6 or less (you should never have less that that) they also need lots of swimming space... so if you are keeping just a few serpaes be prepared for fish like the swordtail (if he’s male) to have his back tail bitten... they will also nip at nearly anything big or small... that’s why they are better in a group- it decreases this... not to mention that they are a schooling fish so for a ton of other reasons they can’t be kept to just a couple... your tank I’m afraid is too small to keep these kinds of things... I would see if your pet store will take them back (once the Ich is gone) and re start... but make sure to stock it with suitable fish so they will stay healthy... could be most likely why you got the ich... ich is often brought on by stress... some people don’t quite understand how ich actually works... the basics is that everyone of those little tiny spots you see is a spore... it will burst and release thousands and thousands (if not more) tiny little bacteria that infest everything in your tank... decor, gravel etc.... then when a fish swims by they reattach to the fish causing another spore to develop... and the process repeats...however these bacteria can not live off of a fish for more then 24-48 hours... so it’s best to 1- quarantine new fish first and 2- keep a very close eye and inspect your fish everyday... (ich usually starts on their fins) if it’s not treated properly it will kill your fish... so even after your fish shows no symptoms anymore you need to do a decent cleaning (without getting rid of all your BB) to make sure the little bacteria aren’t hanging around...

Also, was this tank cycled or are you attempting a fish in cycle?

 

Also, was this tank cycled or are you attempting a fish in cycle?

One albino Cory, panda Cory and false Julio Cory.

Tank was cycled months before this happened. I think one of the new serpae I brought in about a week ago had a fungus and that’s how my swordtail got it because he was a strong fish and the alpha of the tank. No serpaes messed with him.

 

You can’t keep those Cory’s... that is cruel... they need to be a minimum of 6 of each of their OWN kind.... that is severely unhealthy and they will suffer... possibly die even... whoever sold you those should not be working in any fish store.... just my opinion....
and if your tank is cycled why do you have ammonia?? And that wasn’t meant to sound rude to you... it’s these people working in the **** stores... if your going to sell fish you should know these things...

Also how do you know they didn’t? You can’t watch them 24/7... they may have done it in the night or when you were not watching... that’s all
Are you always getting 0.25 ammonia?
Either 1: your tank isn’t actually cycled
2: you stocked too many too fast (and overstocked)
3: you changed out some kind of filter material that you shouldn’t have...
You should never show ammonia in a cycled tank...
what kind of filter is it?
One of those ones that tells you to replace the prepackaged little cartridge every couple weeks?

 

One albino Cory, panda Cory and false Julio Cory.

Tank was cycled months before this happened. I think one of the new serpae I brought in about a week ago had a fungus and that’s how my swordtail got it because he was a strong fish and the alpha of the tank. No serpaes messed with him.

okay so try to give the albino cory and the panda cory back because those two get the biggest and get 1 more false julio cory. is there any other fish in the tank?