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What is a/the key faktor what makes eggs so fragile?
I have some Hypancistrus Inspektor eggs at the moment and just by looking at them they burst.
My females have been carying these eggs for at least 1,5 years before finally spawning with my new males (introduced in the tank 2 months ago).

I have had 2 spawns now. The first batch didn't make it. The eggs I have now are extremely fragile. They also look a bit pale, at first I thought the weren't fertile but they are. A little embryo has started to show.

I have heard of egg shells being to tough because of high conductivity. Could it be the same the other way round? Although I have never had this problem with other Hypancistrus eggs so far. My conductivity is around 300 microsiemens.
Or could it be that the eggs are not of a great quality?

This is where TDS, conductivity, and osmotic pressure play a role. Eggs are semi-permeable. This means they selectively transport waste, gases, and other assorted items through the membrane while preventing other necessary (or potentially dangerous) molecules from passing through the membrane. As a result, excess molecules in the water column creates an osmotic differential across the membrane causing either loss or gain of water in an attempt to equalize osmotic pressure on both sides of the membrane. The egg will take on more water if TDS in the water column is too low, and lose water if water TDS is too high.

Given that they are spawning, you have to be doing something right. I would let them continue for a couple spawns to verify this isn't being caused by old follicles. If that didn't resolve the issue, then I would look at decreasing the TDS in water change water. I say decrease based on the blackwater origins of the species. It's nearly impossible for most hobbyists to know beyond a shadow of doubt the direction of osmotic flow across the membrane.

Thank you very much for your reply. It answers my question and confirms my own thoughts on the eggs.

One of the eggs hatched yesterday, very premature...(maybe 2 days) The larvae is alive still this morning. Hope the next round of eggs from these females will be tougher.

I now have a second spawn of one of the females that spawned before, a few weeks ago. So these eggs are "fresh".
The male took care of the eggs for 3 days and this morning he was out of his cave and the eggs were also kicked out. I didn't touch the eggs but scooped them up with a small cup and placed them in an egg tumbler. When I just looked (got home from work) I saw that of 80% off the eggs was leaking or the yolk sack was coming trough the eggshell... The fry are premature, two of them hatched already.

Does any one breed Hypancistrus Inspektor (L102) and experience this same problem of fragile eggs?
What worked for you to keep the eggs from damaging?

Any help would be appreciated.

Hi Jac!!

What are the parameters of the water??

As Larry stated the solution lays there
Cheers
Yann

I just noticed that nothing had been mentioned of temperature in this tank. A temperature even slightly too high will cause the embryo to mature at a faster than normal rate. I read a paper somewhere, don't remember the reference, which showed a doubling of the metabolic rate with only a four degree celcius increase. That was with a cool water species, but stands to reason the same could hold true with all species to varying degree. When combined with the osmotic pressure mentioned in my previous post, it's not unusual to find fry hatching at a much earlier age. I can't guarantee that is what's happening with this species, but have seen it in the past.

Larry

Goodmorning Yann and Larry!

From the point of the actual spawn to day 3 ( he kicked the eggs out and I put them in the egg tumbler) nothing changed as far as water parameters. It all happened in the same tank/water. At the moment of discovering the eggs they were looking fine, shiny, closed, as they should look at that age.
The parameters of my water are: PH 7,2 KH (hardness) 3 and conductivity is around 300. This is normal tap water. I never test nitrates or ammonia or any other parameters, so if others are required I will have to buy some tests first I do a 100+% water change over the week, consisting from 2 times a cold water change of 25% and once a week a waterchange of 80% with warm water. So I guess levels will be low. Temperature in the main tank is 30 degrees celcius.

After discovering the leaking eggs I put them into my "incubator tank". This is a small tank of 5L, filled with tap water and temperature 28 degrees celsuis. I change waters in this tank twice a day. And I managed to save 7 fry in this way. Even some fry with the leaking egg yolks. I didn't make any pictures but when I say leaking egg yolks I mean the outer egg shell was torn but the actual egg yolk attached to the fry was still intact, it was herniated.

I use and play with the temperature to my advantage. When I see eggs are premature in hatching I turn down the temperature by one degrees so they will slow down in development. When I see eggs are suffering from fungus I turn up the temperature so the larvae will develop a little quicker so I can get rid of the fungus without using medication. One degrees will delay or speed up the process by approx. one day, at least that is my experience. I have used this technic for years now and works well for me.

I would like to know how I can improve the outer egg shell from my Inspektor eggs so they don't burst so easily. I also hope the male will improve his care and will do the job himself until the eggs hatch. This is the best way but not always how it plans out.

Hi Jac!!

Maybe the water is too basic & hard considering the geographic origin of these fish??
That would be about the only possibility I would see!!
But I am not worried they are in good hands with you!!
Cheers
Yann