Neurergus eggs: The Good, the Bad and the Ugly

[jennifer]

OK, my N. strauchii (1:2) have amazingly produced over 100 eggs in the past 6 days. Unfortunately, the vast majority are infertile. My husband has an good camera and took some photos for me.

First some bad eggs, of various appearances:

In the past 2 days, some of the eggs laid are fertile. Here are two photos of some good ones (still mixed with some duds I think):

Now, the questions for the people who have ever raised this species:

Is it OK to keep the eggs at 17C (thus warming them from the 11-14C temperature of the adults' tank)? Is it OK to remove the eggs from the rocks? This does not seem to damage them.

Anything else I need to watch for? I am keeping them in dim light, as Frank suggested. Most are in flowing water.

 

[henk]

Jennifer I have rarely seen Neurergus eat their own eggs and the larvae are very quick swimmers. I rasied my larvae in the parentla tank without troubles, but the bottom had peddles/stones between which the larvae could hide. I would not touch upon the eggs from the rocks. If you want to get them out of the parental tank after all, I would rather take out the whole rock.

These eggs are very sensitive to saprolegnia and to being eaten by flatworms (which was my main problem). Strauchii indeed lays betweehn the temp's you are telling 11-14 till 15°C, if tem goes up they will stop. Baranii lays eggs in much cooler temp's around 5 to 7°C already (nature).

 

[jennifer]

Thank you, Henk. I also notice that the adults are not eating the eggs. The group of eggs in the last photo are still on the rock, but moved to a different tank at 17C. If they do not lay too many more eggs, I will try leaving the rest with the adults. Do you know approximately how long the eggs take to hatch?

 

[henk]

It depends alot on tempreture (regulating the speed). I lost my measurements when my laptop was stolen sopem years ago. To my experience hte adults will lay eggs over a longer period depending on the temperature . With me they continued to lay eggs over more then a month at temperatures between 12 and 14°C.

 

[sergé]

Henk...where do you get the 5-7 degrees for barani from? Nature? Where is this cited?

 

[john]

Congratulations Jen, and good luck with them

.

 

[jennifer]

Update: here are some photos of the strauchii larvae. I lost a LOT of eggs, with less than 25% reaching hatching. Many were infertile. More perplexing, some began development, but had gross abnormalities (large, fluid-filled pockets), or simply died at random ages before hatching.

I found no obvious difference between eggs left attached to the rock versus eggs scraped off the rock and kept in tubs. The ones in tubs hatched a lighter color (the tubs were on a light-colored background), but otherwise the larvae and % hatched seem the same (I did not do exact counts).

It took roughly 4 weeks from laying to hatching at a temperature of 16-17C. At hatching, they emerged ready to start eating. They take small daphnia and copepods readily. I'm not sure if they are eating the chopped blackworms yet. I have had no deaths among the hatchlings, so they appear to be quite hardy at this stage.

Please do not write asking for offspring. This year's litter is not mine to disperse.

 

[juraj]

Very interesting. Thanks for sharing.

 

[TJ]

Really fantastic, Jen!

I hope you coax get your husband to take some close-up shots of the larvae...

I see what looks like an air tube. Are you using a filter or airstone or just doing water changes?

 

[jennifer]

Tim - I'm just using an airstone and doing siphoning to remove debris. Most filters suck up daphnia, so I don't use them with larvae at this stage. I wouldn't even bother with the airstones, except that this is a stream-dwelling species, so they may appreciate good oxygenation and a bit of movement.

 

[sergé]

I saw how a german succesfuly raised the larvae of N. s. barani. He did it in flat plastic containers (10 cm high with only 5 cm of water and 60x30 cm floor) with a few hiding places and just an airstone. So your technique is good.

 

[jennifer]

Here are photos as of today...

 

[ralf]

Very nice pictures. I keep my fingers crossed for the further development of your larvae.

 

[hayden]

Wonderful Jen, very cute little guys.

 

[joseph]

All I can say is congratulations Jenn! Do keep us updated.

 

[jennifer]

Three-and-a-half months old, and the eldest are starting to color up nicely. Funny, though, they don't really look like the juvenile color pattern. The spots seem to start out rather large and blotchy.

(Message edited by jennewt on June 01, 2005)

 

[david]

Looks like they're coming along nicely Jen