Strange Deaths

[Izzysammy]

I have a 20gl freshwater tank that's been set up for awhile now.
I have 4 ghost tetras
4 zebra danios
2 platies
And 1 rainbow shark

All of the fish have been established in the tank for awhile and the 2 platy are the newest editions (they were added about 2 months ago)

I did have 2 mollies in my tank for a long time and in the past few days my 2 mollies died and today one of my platy looks bad.
All of my water paremeters are perfect and I do weekly water changes. It seems so out of the blue and I don't know what is wrong.
The only thing I can think of is that the shark is bullying them so much that they are stressed to death.
I see him chasing my fish around a lot and that seems like the only plausible explanation. He doesn't chase my tetras or danios. But he is very territorial over the main ornament and chases the mollies and platies around.

Does anyone have any other theories? And if it is my rainbow shark is there anything I can do to make him less aggressive?

 

[mimiheart]

20 gallons is too small for a rainbow shark. They need to be in 40+ Double check there are no sores or ich spots on any of your fish.

 

[Potluck]

I would bet the shark is killing them as they are aggressive no matter what people tell you, I had a retail that would attack fish during the night cycle
Any sign of
Labored breathing
Not eating
Enlarged stomachs (bloat)
Pinecone scales
Abnormal poop
Lathargy
Any external signs like white spots
White fuzz
Lesions (sores)


What are your water parameters and what are you using the water with? If strips they are not accurate and should get an api master liquid test kit.
But yes I would put the money on the shark as they are jerks

 

[Izzysammy]

I would bet the shark is killing them as they are aggressive no matter what people tell you, I had a retail that would attack fish during the night cycle
Any sign of
Labored breathing
Not eating
Enlarged stomachs (bloat)
Pinecone scales
Abnormal poop
Lathargy
Any external signs like white spots
White fuzz
Lesions (sores)


What are your water parameters and what are you using the water with? If strips they are not accurate and should get an api master liquid test kit.
But yes I would put the money on the shark as they are jerks

Yes I'm pretty sure it is him.
The only real sign the fish have shown is labored breathing and hiding in corners

My nitrite, nitrate and phosphates are all 0
And my ph is above 7.6
I use API test kits that are the liquid based ones.

Yesterday after I noticed the platy acting sick I decided to go to the store and I got more plants and hiding areas.
I did a water change and rearranged the whole tank.
Everyone has a lot more hiding places and room to swim now with the new configuration.
Today I woke up and saw that my platy was swimming normal again!
And the shark seems to have claimed the old decoration as his own but he is looking less aggressive since I changed the tank around.
Hopefully this will solve the issues.