Urgent help needed

[vijayw]

Yesterday morning found one red cap oranda dead and partially eaten. She recently recovered (I feel) fin rot, and returned to main tank few days back only. Removed it and changed some 20% water.

Now today found one sucker fish struggling. Not able to stick to anywhere vertical. Lying on substrate and then others (tinfoil) picking it.
Just remove it in a separate bowl. It's lying there motionless. But alive.

How to revive him?
What to do???��

Don't have any tool to measure water parameters.
Water looks clean. Transparent. Top filter. Temp around 30 deg C.
Tin foil, tiger barbs, koi, an angel, 3 red cap and 1 more sucker fish.
It's a 30G tank.

 

[vijayw]

In bowl, it is still struggling to stick to side. I put a little salt in the bowl. Water is cold. Don't have a separate heater for this bowl.

It's a small one only - 1.5" length.

 

[vijayw]

Photo of fish in bowl.

 

[charliebankston]

Its possible that whatever killed the oranda has sickned the pleco. Since it was partially consumed, I'll assume the plecos did most or all of that because that's what they do.

 

[vijayw]

Its possible that whatever killed the oranda has sickned the pleco. Since it was partially consumed, I'll assume the plecos did most or all of that because that's what they do.

�� lost that pleco as well during the day (in separate bowl).

The (dead) oranda was found floating in the morning.

Something very fishy happen in night, day time ita all goody-goody.