Angelfish fry die before free swimming

[TiagoRibeiro]

I have a pair of angelfish in a 20 gallon tank with only a spawn cone, heater and sponge filter. They breed very often and succeed in laying eggs and fertilizing them. The fry reach the wiggler stage and the parents do a good job. But when they start to become swimmers they simply die... ? They are not eaten by the parents... they die in the bottom of the tank and then become rotten...

The first ones are trying to swim short distances but the parents are always grabbing and putting in the spawn cone. In the next morning almost 90% of the fry are in the bottom of the tank appearing to be very weak. Later in the day, they are all dead...

What do you all think is causing this?

Thanks in advance, and sorry for my English ?

 

[SaraB]

What are your water parameters? What are you putting in the tank for the fry to eat? Fry are super sensitive.

 

[TiagoRibeiro]

Hi, thanks for the help. The water parameters are all ok. Amonia 0, PH 7... I do daily water changes (25%).

I haven’t given any food... I thought it was only necessary to feed the fry after they are free swimming. They never reach that phase, I think...
I have newly hatched brine shrimp ready... but I’ve never used it because all the fry died first.
Maybe I should have started the food early?

 

[SaraB]

I misread, I thought that you said they die after being free swimming.

 

[yaya16]

Hi
My best guess is that they are dying of hunger. It is not always clear when the yolk sac stage is over and it is good to start feeding a bit earlier. Just throw in artemia on the day before they usually die and see what happens. Of corse it will be better to separate them from the parents and put them in a small plastic container with airstone. This way feeding is much more efficient and you can monitor the fry easily. I would do 100% water change everyday for about two weeks and then move them to a small tank.

Hope this helps and good luck!

 

[TiagoRibeiro]

I suspected that... but I was told to not feed the fry before they are free swimming...
They are preparing the next batch of eggs, when do you think is the best time to start hatching the brine shrimp? How many days after the spawn ou how many days after the hatching of the eggs?

 

[yaya16]

I am not an anglefish expert at all but I did and do breed other egglaying fish. Hatching and growth is directly dependent on temperature. from a paper I found, in 24-25 degrees C, angelfish larvae may start feeding on the third day post hatch which essentially means you want to start your artemia culture on the 2nd day after they hatched so you will have it ready by the next day. But this is theoretical. You know from experience when they start to die then give them the artemia a day before that. There could be a number of other factors influencing the fry which are much more sensitive to water quality than the parents but this is the first thing I would test.

Note that fish are less sensitive to the conditions then they are to changes in the conditions so try to think if are any factors influencing water quality during the time the eggs and fry develop. You could try different things as a small experiment, remove some of the larvae from the tank to a container and leave some in the tank, fill the container water with 25% tank water and 75% clean (chlorine free) freshwater and see if you get a difference in survival. Feed and water quality are the two main things you want to change for improved survival. Another possible factor is aggressive water movement (such as strong bubbling from the sponge filter).

Let us know if you made any progress!

 

[ghyti]

Angelfish eggs hatch on day 3 after being laid. They go free swimming on day 8 or 9. They do not eat and should not be fed before they are all free swimming. The extra food just fouls the water. If they die before going free swimming it is probably a water parameter problem or could be lack of oxygen in the tank. If Nitrates are high it could affect the babies and not the adults. One solution to the whole problem is to pull the eggs and raise them yourself.

 

[TiagoRibeiro]

They are in a stripped tank only with the parents. I don’t have a Nitrates test, but I think it’s fine. I do do daily water changes and feed a small amount of food. The water is well oxygenated, I have a sponge filter with the outake pointing at the surface of the water.

 

[ghyti]

One other possibility that you won't want to hear. It could be just weak parents. I've had pairs like that, everything looks great but the babies just don't develop. Do your best to be sure the parents are healthy and feed them plenty of good nutritious food. Try feeding Tetramin flake for a couple months, it may help.

 

[TiagoRibeiro]

It’s a possibility... ��
I’m reading a lot about this and narrowed it down to :
- they died of hunger (I’m going to feed a bit earlier)
- fungus or bacterial infection (I don’t have methylene blue, is there an alternative? Perhaps Hydrogen Peroxide?)
- weak genetics of parents

 

[ghyti]

You don't use anti-fungals in the tank with the parents, only if you pull the eggs. Could be bacterial but it sounds like you have pretty clean water. Water changes never hurt. Can't be starvation, baby angels will live for three days after they go free swimming without food. Feed too early and you just foul the water. You are feeding the parents right? The parents will see that the babies get food if necessary. Sound like weak genetics is probably the cause.

 

[TiagoRibeiro]

I’ve noticed that the parent left 3 or 4 white eggs, and it started to spread into a small cotton-like cloud... that’s why I thought of fungus...