I have eggs! How do I do water change?

I noticed today I have a couple of inch by couple of inch cluster of eggs on the glass inside my tank - must have popped up very quickly over last day or two as seen nothing until now and they're in a really obvious place! My guess is that they're Cory eggs - significantly improved their diet recently, plus been recently using prefiltered water as my tap water contains nitrates - guessing the improvements made them happy enough to breed? The only other species it could be is my zebra danios, but the eggs look too big, the cories seem more likely.

So my question - I'm due a water change today. My usual water change takes the water level down to about halfway down the tank. However, the eggs are stuck to the top third of the glass - so I don't see how this is doable considering the eggs would be out of water for a while during the change. What am I supposed to do?

Also I recently ordered a broad spectrum medication for some sort of possible fungus on a single cory (doesn't appear to have spread to others) - the medication has come but is it safe to use with eggs in the tank? Especially if I don't know for sure if I actually need it - unwell cory seems to be improving and also appears to have gained wait (had suddenly been looking worryingly concave)

Help really appreciated asap as I need to know what to do re. water change. Please and thank you!

If the eggs are stuck to the glass they are not danio eggs. Danios scatter their eggs in plants, cories stick them to the glass in small groups.

Don't use medication on fish eggs or fry because most medications will harm the embryos.

If the sick cory is improving without medication, then don't treat it for a week and see if it continues to improve without medication. If it does continue to improve then you won't need to treat them.

If the eggs are really close to the water surface don't do a water change. If the eggs are a few inches below the surface you can drain the water down a bit so the eggs remain underwater, then top the tank up. Alternatively don't bother with the water change until after the eggs hatch in a few days. If you normally do regular water changes then waiting a few more days won't make any difference to the fish.

Thanks so much! Will keep an eye on the unwell cory but won't use medication unless necessary. May post some photos later! Can possibly do a very small water change as the eggs are a couple of inches below the surface - but I do do weekly water changes generally so if the eggs do hatch that quickly maybe I'd be better off waiting till next week? Will try to get photos of the eggs and the unwell cory asap

You can get like your credit card or your finger and very lightly take the corydoras eggs off the glass and put them in their own tank as they will be eaten by anything. Or do you have like a razor? I use my fingers when they first lay as its sticky and won't break, but I have very delicate hands and know when to stop.

Thank you! I currently don't have a separate tank but by sheer luck a few days ago someone I know mentioned he's getting rid of one with pump and everything included so I'm hopefully snapping it up and will set up asap! I'm new to cycling a tank as got this one secondhand already set up with fish, and managed to transport most of the existing water. Can I speed up the cycling process by water changing the current tank (once the eggs have hopefully hatched) and using the water in the new tank?

I'm not sure I trust myself to successfully scrape the eggs off the side without doing more harm than good - however I can't do this yet anyway as nowhere to scrape them into. I do have some exceptionally sharp toolkit blades if it comes to it though. Some eggs do appear to have been eaten but the majority are still very much intact and have grown overnight I believe!

I've been taking this 'owning my own tank' process one step at a time but was no way anticipating eggs yet! Does the egg-laying mean that the cories are happy? My main question at the moment is if I can get them to hatching point, what do I do with them?? Not sure if I'll even be able to get the second tank in time, let alone get it cycled enough! I know you can buy things to attach to the inside of a tank that I could order with fastest delivery, would this be worth getting for the meantime? And if so - how on earth do I capture all the babies? Any tips, or is this just a very patient process with a net and good eyesight?

Please and thank you!!

IndiaHawker said:

Thank you! I currently don't have a separate tank but by sheer luck a few days ago someone I know mentioned he's getting rid of one with pump and everything included so I'm hopefully snapping it up and will set up asap! I'm new to cycling a tank as got this one secondhand already set up with fish, and managed to transport most of the existing water. Can I speed up the cycling process by water changing the current tank (once the eggs have hopefully hatched) and using the water in the new tank?

I'm not sure I trust myself to successfully scrape the eggs off the side without doing more harm than good - however I can't do this yet anyway as nowhere to scrape them into. I do have some exceptionally sharp toolkit blades if it comes to it though. Some eggs do appear to have been eaten but the majority are still very much intact and have grown overnight I believe!

I've been taking this 'owning my own tank' process one step at a time but was no way anticipating eggs yet! Does the egg-laying mean that the cories are happy? My main question at the moment is if I can get them to hatching point, what do I do with them?? Not sure if I'll even be able to get the second tank in time, let alone get it cycled enough! I know you can buy things to attach to the inside of a tank that I could order with fastest delivery, would this be worth getting for the meantime? And if so - how on earth do I capture all the babies? Any tips, or is this just a very patient process with a net and good eyesight?

Please and thank you!!

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Adding water to another tank doesn't speed up the process. Most of the BB is in the filter pads. They are happy if they lay eggs, but they are very hard to find! I breed corydoras so when they hatch it's like a tiny tadpole! Anyone will eat the little ones unless you can put them in another tank. I would put the eggs in another container with an air pump.

If you get another tank, you can half fill it with water from your current tank and top it up with dechlorinated tap water. Then take half the filter media from the established filter and put it in the new filter. Add more new filter material to both filters to fill them back up. Then add fish from your current tank.

If you want new fish then set up the new tank with clean dechlorinated water and aerate/ filter it for 24 hours. Then add half the established filter material from the established tank. Top up both filters with more media. Then go get yourself some new fish.

The established filter material that gets moved across will cycle the filter for you and you shouldn't have any issues with ammonia or nitrite.

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Don't try to move the eggs because you are more than likely to damage them. They will hatch in about 5 days (depending on temperature) and the fry will sink to the bottom and live on whatever is there. If you have lots of plants in there some should survive. You can get a liquid fry food for egg layers and add that to the tank when the eggs hatch or you can make up some from a boiled egg.

Boil an egg for 10 minutes and eat the white bit. Push the yellow yolk through a handkerchief into a small container of dechlorinated water. Put a lid on the container of water and egg yolk and shake it up. Use an eye dropper to suck up some of the mixture and squirt it into the tank so it sinks to the bottom. Do this 3-5 times per day. Keep the egg/ water mixture in the fridge and discard any unused egg/ water mixture at the end of the day. Boil a new egg and make a new mixture each day.

Reduce filtration and water movement when feeding and put a sponge over the intake so you don't suck up the fry.

After a couple of weeks on egg yolk you can add microworms and newly hatched brineshrimp to the tank.

There is more information about culturing fry foods at the following link. Most take a few weeks to get going so won't help now but can be used in a few weeks when you get more eggs.
http://www.fishforums.net/threads/back-to-basics-when-breeding-fish.448304/

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Don't gravel clean the tank for the next few weeks or you will suck out the babies. You can still do water changes but limit yourself to 20-25% water changes and do them every couple of days.