Mystery Fish Deaths In Established Tank

[webjen]

I've been keeping fish for almost 25 years and am baffled and frustrated here. I've got a 65 fresh, exclusively tetras except for an otie cat and tiger pleco. Live plants, emperor filter and bubble wand for extra air. Everythings been fine for well over a year, even my neons are happy. However, I've been having fish start to wither and some have died. Their color fades, they stop eating, some get bloated, some don't. I cleaned the filter, water change, used some stress coat and copper (which usually works), and still not seeing improvement. I've only lost 1 neon, and those are the canaries in the coal mine far as I'm concerned, but white skirts, del rios, diamonds, not happy. temp 80, pH and hardness neutral (where it always is), no nitrates, ammonia, etc. what gives? no signs of fin loss, fins sticking out (even when they're bloated), no signs of bacteria or flesh disease far as i can tell. The only thing that's changed is one of my t5 bulb burnt out a month ago and was on backorder so I had two 10000K bulbs until the colormax bulb came in. the old bulbs were worn out, over a year old. Could new, bright light be affecting them? sounds weird but that's all that's changed! any advice greatly appreciated. i've put too much money, time, and heart into this tank to lose it!

 

[Miss Wiggle]

sounds like a bacterial infection to me, have you tried a strong bacterial med?

how big is your tank and what model filter is it?

 

[WILDER]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.
What do you feed your fish.
Do the fish act listless and lethagic.
What does it look like when the fish go to the toilet.
Check the fishs anus to see if it enlarged or red and inflamed.
Can the fish maintain there balance in the water.
Any sores or red streaking on there bodies.
Any signs of flicking and rubbing.

 

[webjen]

it's 65 gallons. almost all tetras, not nearly anywhere near the max i can have in the tank. i am zero on all tests for nitrate, ammonia, etc. pH around 7, hardness right in the middle. like i mentioned, nothing has changed, and i haven't added any fish in the last month. i too am beginning to think it's a bacterial infection since they don't eat, they're sort of lazy and near the top, and i can't see any signs of trouble (no discoloration, no weird lesions, etc). i work all day so i couldn't tell you about their excrement, nor would i even know if it was different than normal since i don't look for that ever. The question is, if it's bacterial, should i pull the fish that look affected or treat and wait? not sure how much this thing will spread, it hasn't gone very far yet...thanks for the replies...

 

[WILDER]

Do you have live plants in the tank. What your tap nitrate reading.

Signs of a bacterial infection with no symtoms are.
Being listless and lethagic.
Pale or darker in colour.
Long stringy white poo, but can also mean other things.
Heavy breathing.
Not eating.
The fish will try to get of the bottom of the tank but just sink back down.
Laying to oneside.

If you think its a bacterial infection and with losing quite a few fish I would add a bacterial med to the tank.

 

[Miss Wiggle]

def start treatment with a bacterial med

 

[webjen]

thanks so much for the replies. i did start with Maracyn-2 for gram negative bacteria and hope it works. I also hope it doesn't kill my neons, since I know they're sensitive to meds! Fingers crossed!

 

[WILDER]

Its more the parasite meds with neons.
Good Luck.