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'Rio Ucayali' BN Fry deaths - advice?


Colour_genes

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I purchased a couple of young 'spotted' bristlenose at the start of 2015, they were being sold as starlights, but they do not have any white edging to the fins, just a small rusty orange-red tip and general 'undertone' to the dark brown body colour. From looking at other posts etc, pretty sure they are what are being called 'Rio Ucayali. Anyway, they have matured into a pair, and have now bred for the first time.

There has obviously been a problem of some sort however, as this morning I noticed a dead fry at the entrance to the 'cave', and by the time i had finished siphoning there were between 25 -30 dead fry spread across the tank, mostly near the front. There are still some live fry, I have counted 6 -8 on the glass of the tank and there may be more in the cave, which the male is still fiercely guarding.

Has anyone else who has successfully bred these had a similar problem, and what do you think may have caused it? I have tested water parameters (23oC, 6.5 pH) and there is no ammonia or nitrites detectable. The tank is 70cm x 35cm base, has a shallow layer of gravel, several live plants (java fern, java moss, ambulia), 3 large sponge filters, and a range of hides and shelters. Gets some indirect natural light from skylights during the day, sufficient for the plants to grow and look quite healthy. There are also 25 or so guppy fry less then a week old in the same tank, with their parents, and none of those have died or look unhappy at all. I wondered whether the standard sized terracotta cave may have been too small to keep enough water/oxygen flowing over that many fry? Or the fry were not mature enough to leave the cave? You can see in the photo that the live fry have quite yellowish bellies, is that the yolk that has not been totally used up yet?

Any suggestions to improve survival rate on the next lot of fry much appreciated.

 

2016 Rio Uc cave DSCN5088.jpg

2016 Rio Ucayali dead fry DSCN5119.jpg

2016 Rio Ucayali Fry DSCN5085.jpg

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This evening I can see 3 or 4 more dead fry near the cave entrance, also counted 8 live fry on the glass, so probably a few more I can't see as well.

LA - Not sure exactly how old they are, didn't see parents spawning and took me a few days to realise the male wasn't coming out of the cave. But this is the first time (ie yesterday morning) I have seen any fry outside the cave, so not very old at all. Have been feeding blanched green peas 2 days a week and mix of JBL, Omega One or Wardleys 'pleco/ algae tabs' on the others. Will start adding a slice of courgette or cucumber from now on.

Cam - Quite possible the male has inadvertently chucked them out before they are ready - I did see him zoom out of the cave, chase the female away from some food, then dash straight back into the cave at high speed last night,  would have thought it was a bit rough on any fry still in there

Alexay - Don't have a Nitrate kit atm (run out) , but typically low (I do a 20 -25% water change weekly.) Feeding as above, but the fry have not been out of the cave to feed before this (unless they have all been sneaking out after dark, and then all heading home in the morning!), so don't think that is the problem. Rechecked the thermometer from a better angle (down on my knees !) and temp is probably closer to 25oC in fact; would you suggest higher?

Thanks for the feedback / suggestions.

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It is a food transition issue.  Sometimes the male can actually keep them to long in the cave, and they starve.

you need some of the soft food, rather than the Pleco chips, as the chips do not spread around the tank like the tab food does.

zucchini is better than cucumber as the cucumber is already higher in moisture than the zucchini, and fouls the water quicker.

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Thanks for the advice everyone. As I have a copious supply of home-grown zucchini, I am putting several slices in the tank at a time and replacing them daily. Can't see any live fry atm but there is plenty of cover where they might be hiding, so will just wait & see. Male fish is out of the cave and resting & eating around the tank, will hope for more eggs soon, and a better result the next time around.

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