Dwarf Gourami - Not breathing normally

Hello guys,

I am a beginner to fishkeeping... I have a 100 liters tank with

2 Tin foil barb
2 Angel Fish
1 Marble veil Angel
2 Dwarf Gourami
4 Silver Shark

last week i forgot to turn on the filter after feeding and then found out that the 2 tin foil barb and a silver shark is dead. I moved all the other fishes, cleaned the tank and changed the gravel completely. then following happened:

Day 1 - 1st Angel Dead
Day 2 - 1st Gourami Dead due to mouth fungus

I started giving 2ml of API Melaflix daily for 3 days and stopped
Day 6 - 2nd angel started lying low.... I isolated it..

Pictures and video attached.... now the fish goes down and then comes out of the surface and looks as if it takes a quick gasp.

Thanks in advance

Did you cycle the tank?
Allmost all fish aren't suotable for a 100 litre tank btw (in fact only one DG).

DoubleDutch said:

Did you cycle the tank?
Allmost all fish aren't suotable for a 100 litre tank btw (in fact only one DG).

Click to expand...

Yes, I did it a week ago.... the water still looks pretty clear.

The local vendor advised not to cycle completely, so did a 40%...

Not suitable as in... I have another 30litre tank as well... do you want to shift into that?

Not suitable as in : The all grow to big for a 100 litre tank. For instance https://www.seriouslyfish.com/species/barbonymus-schwanefeldii/

My guess is the cycle / filter couldn't cope with the pollution these fish caused.

First proper cycle and then get smaller fish.

Also: Bala sharks are very sensitive to water changes, adding them as starter fish is not a good idea. If you really want them be prepared to rehome them when they grow too big or upgrade your fish tank. And BTW - they grow faster than you'd think.

Can't comment on the rest as my gouramis are unkillable

Dephea said:

Also: Bala sharks are very sensitive to water changes, adding them as starter fish is not a good idea. If you really want them be prepared to rehome them when they grow too big or upgrade your fish tank. And BTW - they grow faster than you'd think.

Can't comment on the rest as my gouramis are unkillable

Click to expand...

And also need a tank that is 8 times bigger than this tank.