Re: discovery of a gbr nest: what's next?
Posted: Sun Jul 20, 2025 2:29 am
With cories in the tank, the chances of fry surviving are slim, unless you're extremely fortunate. The eggs are generally devoured, but should they hatch, the fry are highly vulnerable to cories, both day and night. I recall a particular instance where I witnessed a female blue ram attempting to protect her four-day-old fry, only to be outmaneuvered by two cories that appeared out of nowhere, resulting in the swift disappearance of the fry.
The eggs are especially susceptible to predation at night, given that cories are nocturnal, while rams are not. This means the rams are unable to safeguard their eggs or fry during this time. I've personally lost four clutches of ram eggs to cories overnight.
I must stress that leaving the light on is detrimental to the well-being of all fish. I've known instances where this practice has led to outbreaks of ich, as it causes immense stress. Fish require a period of total darkness, a fact I've discussed in detail elsewhere.
On a more positive note, the suggestion to add dried leaves is an excellent one. Research has shown that fry develop at a faster rate in tanks with dried leaves. The infusoria produced by these leaves is one reason, but the bacterial protection provided by substances within the leaves is also likely to play a role. I collect dried oak leaves from my garden every autumn, where I can be certain they're free from chemicals and pesticides. I've successfully raised cory, characin, cyprinid, and Farlowella fry using only the food produced by dried leaves and the tank's biological system.
The eggs are especially susceptible to predation at night, given that cories are nocturnal, while rams are not. This means the rams are unable to safeguard their eggs or fry during this time. I've personally lost four clutches of ram eggs to cories overnight.
I must stress that leaving the light on is detrimental to the well-being of all fish. I've known instances where this practice has led to outbreaks of ich, as it causes immense stress. Fish require a period of total darkness, a fact I've discussed in detail elsewhere.
On a more positive note, the suggestion to add dried leaves is an excellent one. Research has shown that fry develop at a faster rate in tanks with dried leaves. The infusoria produced by these leaves is one reason, but the bacterial protection provided by substances within the leaves is also likely to play a role. I collect dried oak leaves from my garden every autumn, where I can be certain they're free from chemicals and pesticides. I've successfully raised cory, characin, cyprinid, and Farlowella fry using only the food produced by dried leaves and the tank's biological system.