i have 15 pairs of oscar fish which feed with frozen
beef heart, without any supplement.
and keep in the water with under 5 degree hardness
and 7 ph water without change water to 1 moon of it.
but only one pair of them regularely spawing and hatching
their eggs. but some of them sometime spawing and not haching
question?
1.is the problam because of hardness under 5 dh
water pairs or lack of vitamins or minerals?
2.i use from astaxantin,cantaxantin,zexantin
powder for livebearers fishs and other fish
whit out adding vitamin permix and minerals
to biomar fish food (granuls dry fish food)
which cause increasing fry in livebearers
but in other fish casuse stop or not hatching
eggs.
what is the problam?

Welcome to OFL. Um ... I'm not sure if I understood that right but kind of sitting here with my jaw dropped.

Your fishes' diet consists of solely beef heart and carotinoids, is that right? No idea if it's the main cause for the Oscars not spawning or the eggs not hatching, but I would sure think that can't be healthy. Thinking how Oscars that regularly spawn in the wild certainly have a varied diet of insects, crustaceans, fish, plant matters and fruit etc., and not frozen cows only, so I would think a diet like that would be healthier.
Sorry if I understood that wrong.

Also, how big are your tanks? I would not expect the hardness or pH to be a problem, but what about nitrates for instance, do you test your water for that?

15 pairs, that 30 oscars, i hope you have a massive tank/pond. Varying the diet is always a good idea. Check out some other threads on what to feed oscars. I have no experience with breeding oscars but you should be getting more than 1 pair breeding from 30 fish

30 Oscars?

good luck with that im just thinking how much waste my 7 produce,let alone 30.

keep us posted and please post sum pics so we can see yr O's.

If i were you i would try to feed your Oscars more live food. In the wild Oscars spawn during the rainy season when live food in the form of insects are washed into the river as the water level rises. Try earth worms mealworms and river shrimps as well as any insects you can find in the garden. A large water change with a slight lowering in temperature also mimics that of the rainy season in the wild and often triggers Oscars into spawning.

my oscar photoB)

my oscar photo

[img] my oscar photo

my oscar photo

my oscar photo

If this is the pair that eat the eggs the problem you have may be the lack of gravel in the tank. Oscars dig huge pits in the tank to hide the fry in when they have hatched. If they have nowhere to hide them perhaps they feel that the eggs are too vulnerable and eat them.