My fish are dying one by one

[duanes]

One other thing you may want to consider is the addition of tannins, using peat, or Rooibos tea..
true parrots come from black water rivers (like the Rio Negro).
These cichlids are recent additions to the hobby (compared to angels) so have not built up tolerance for normal aquariums conditions.
In the beginning angels were quite sensitive, but over the century since they were introduced the aquarium strains have become quite hardy,
Hoplarchus have not had that hardening in process yet.

 

[Deadeye]

I consider 30ppm nitrate high, and a 20% water change per week wimpy. I do 30-40% on my system every other day.
Parrot cichlids (if you mean true parrots, Hoplarchus psittacus), come from low mineral content water with undetectable nitrate, so 30ppm for fry could be quite dangerous, and the percent die off could be normal under those conditions.
What is your friends water change schedule? Is he/she, seeing the same proportional die off?

I believe the op is referring to blood parrots or the short body convicts referred to as parrots. It so the water quality (minus the nitrates) is more or less appropriate, though higher ph is best for them.
I don’t think that an all bloodworm diet is necessarily helping either. Probably not the cause of death, but certainly lacking in proper nutrients.

 

[C. Breeze]

To echo the above. To me 30ppm nitrate is high. To me 20 percent a week is… weak.

beyond that- even wild cichlids can have high percentage of bad offspring and especially f1 siblings can.
I’ve had Pairs that would throw less than 50 Percent viable fry- they’d consistently just start kicking off a couple weeks or a month past freeswimming. Split the pairs and reuse them with other mates and the offspring would be fine. Reccesive mutations stacking up so they present themselves in the form of fish that have issues instead Of just carriers with a single copy of the bad genes.

I would address the water quality, and consider a dietary adjustment might be help but you might also just have a bad batch.