Help!! Lethargic cory :(

[Big-j]

Ok I had a group of 5 julii cories, yesterday one was swimming spastically an laying on it's side and then died, now another is just laying down and not really moving, however his dorsal fin, which is usually raised is clamped tight to his body? What's goin on?
My parameters are:
Ammonia-0
Nitrite-0
Nitrate-20-40
Temp-78
Current algae bloom is occurring started about 4 days ago

[xxwolfpackof1xx]

hm stress? your triate are kinda high what size tank are they in and what other inhabitants are there

[fort384]

Tank size, and other tank mates?

pH?

How long have you had them?

[Big-j]

10g with 4 neon tetras (still adding to school)
3 rcs
And 1 male betta
Moderately planted with two filters
Ph is 7.5
I've had them for about a month but the tank has been cycling since christmas

[xxwolfpackof1xx]

if im correct julies get up to 1.5in neons get up to 2 so they may be stressed out from being overstocked but i could be wrong

[xxwolfpackof1xx]

the male betta alone gets 3-5in too i beleive

[Big-j]

Since everyone stays in different zones it's not overcrowded and my betta is super chill

[xxwolfpackof1xx]

well im not to sure as to why your cories are doin that

[Shadowraven]

The algal bloom is not unusual with that nitrate reading, which is a little high. I'm also a little concerned when you say that the tank is still cycling since Christmas.

Just to eliminate some things here, a few questions:

1) Is this green water or is the algae growing on things in the aquarium?
2) Also what color is the algae? It hasn't turned yellow by any chance, has it?
3) Are they discolored in any way anywhere on their bodies or gills?
4) Did you add any salt to the water these fish are in? Salt can be bad for corys.
5) Have you recently changed the filter material?
6) Since you are using 2 filters on a 10-gal, what kind and how strong is the return flow into that tank?

If you are having a problem in your aquarium some fish can succumb before others, while some may never be affected.

[Big-j]

Sorry I said that wrong, it's not that it's been cycling since Christmas but its been cycled and running since Christmas, and the algae is on the tank walls, no green water, the algae is just a greenish color, no salt in water,I gave some of my filter media to a friend and had a mini cycle but levels were back to normal within a day or two, this was a week ago, and the filters are an aqueon HOB 10 and a tetra whisper 3-10

[Big-j]

Another Cory died today, my first one , not the one with clamped fins or nothin Maximus just was dead when I woke up

[Tasha]

oh no!! I hate mystery deaths. I hope you can find out whats happening. They dont show anything wierd on their bodies? All barbs are there? hmmm sorry i cant help...

[Big-j]

Everything seems fine, no cuts, no ripped fins, no discoloration, nothing... Idk what to do

[Tasha]

do a 50% PWC, cant hurt, maybe theres something in there thats not being tested for?! GL

[Big-j]

I'll do that hopefully another doesn't keel over

[angloe1]

Good luck! I love my cories! They are so much fun to watch. Hope all is well with yours!

[Tasha]

How are they doing??

[Big-j]

Fine today the one still has his fin clamped tight though I'm hopin he makes it

[angloe1]

Originally Posted by Big-j

Fine today the one still has his fin clamped tight though I'm hopin he makes it

Good to hear he's still hanging in there!!

[Big-j]

Well he's still hangin in there but his fin is still tightly clamped, he doesn't move much, but I can see him breathing so idk what to do