I've been given a few newborns three weeks ago and wondering if I'm doing something wrong or the fry is just extremely slow growing... they seem to be surviving but the size barely increased over three weeks, despite being fed artemia twice per day.
(I raised a few dozens species of various type and these seem to be the slowest growing I've seen yet.... so a concern if I'm doing something wrong)
Thanks for any help.
Lepomis marginatus fry question
Started by
Guest_mikev_*
, Jul 11 2014 02:58 PM
20 replies to this topic
#2
Guest_gerald_*
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Posted 11 July 2014 - 04:46 PM
Live fresh-hatched Artemia? They lose some of their nutritional value after the 1st molt, a day after hatching. I usually refrigerate Artemia immediately after hatching so they dont molt and grow. If you're comparing dollars to bluegill or other large Lepomis, then yes I suspect their growth rate is naturally slower. Also you can try feeding 4x a day. Those tiny stomachs cant hold much at each feeding.
#3
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Posted 11 July 2014 - 05:03 PM
Thanks, Gerald,
Yes, fresh-hatched, I make it daily. I cannot compare with other sunfish, this is the first one for me.....
but at best 50% growth after 3 weeks seems abysmal.
(params are 80F, TDS=150, pH=7.1 --- per chance anything wrong with these?)
OK, I'll try to provide more feedings with powder food, maybe this will help.
Yes, fresh-hatched, I make it daily. I cannot compare with other sunfish, this is the first one for me.....
but at best 50% growth after 3 weeks seems abysmal.(params are 80F, TDS=150, pH=7.1 --- per chance anything wrong with these?)
OK, I'll try to provide more feedings with powder food, maybe this will help.
#4
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Posted 11 July 2014 - 10:16 PM
I have grown western dollars alongside bluegill and longear. Growth rates very similar for first month. Consider possibility your brine shrimp are sub-par nutritionally so also enhance before feeding out by giving brine shrimp some feed as well. Also, if fry have eaten much in the way of cysts then they may be suffering from the dwindles.
Also consider running two brine shrimp hatches per day, one in AM and one in PM. By 6 hours post-hatch you start seeing declines in brine shrimp nutritional quality.
Also consider running two brine shrimp hatches per day, one in AM and one in PM. By 6 hours post-hatch you start seeing declines in brine shrimp nutritional quality.
#6
Guest_gerald_*
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Posted 12 July 2014 - 03:01 PM
James - I learned (somewhere long ago) that Artemia dont begin feeding until after their first molt, so you cant really enhance them by "gut-loading". Some folks claim that Selco (emulsified HUFA concentrate) sticks to them and thus works even if the shrimp dont eat it. Is there any good evidence for that, or is it marketing hype? http://www.artemia-i...entID=579#selco
Eating Artemia cysts could certainly cause growth problems. When I was at NCSU Jeff Hinshaw was experimenting with yellow perch larvae and found that using a dark colored container helped the fish focus on the Artemia and avoid the cysts (better visual contrast) compared with keeping them in light colored conatiners where the cysts were more visible.
Eating Artemia cysts could certainly cause growth problems. When I was at NCSU Jeff Hinshaw was experimenting with yellow perch larvae and found that using a dark colored container helped the fish focus on the Artemia and avoid the cysts (better visual contrast) compared with keeping them in light colored conatiners where the cysts were more visible.
#7
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Posted 12 July 2014 - 05:13 PM
The goat loading concept may be extrapolated from rotifers. The sticking of nutrients to nauplii may be occurring or the emulsification may be consumed directly. When the brine shrimp are of poor quality some benefit is realized by exposure of additional nutrients prior to feeding out.
When it comes to consuming cysts, I think it occurs starting in the second to third weeks which also the beginning of the window where I like to train fry to consume formulated feeds. It appears you can be sloppy with bluegill during the first week with regards to sloppy harvesting of brine shrimp but there after the fish are not so forgiving again until they area month old.
When it comes to consuming cysts, I think it occurs starting in the second to third weeks which also the beginning of the window where I like to train fry to consume formulated feeds. It appears you can be sloppy with bluegill during the first week with regards to sloppy harvesting of brine shrimp but there after the fish are not so forgiving again until they area month old.
#8
Guest_mikev_*
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Posted 14 July 2014 - 09:59 AM
yeah, it seems that multiple small feedings do help.... did not expect instant results but I do see some fry with larger bellies already, and the fry now stays near the front of the glass waiting for more food... good.
thanks guys.
just one more question: is the fry aggressive to each other? I see smaller fry hiding in the substrate/plants, presumably from larger fry? (all the same age, but not the same size unf.)
thanks guys.
just one more question: is the fry aggressive to each other? I see smaller fry hiding in the substrate/plants, presumably from larger fry? (all the same age, but not the same size unf.)
#9
Guest_centrarchid_*
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Posted 14 July 2014 - 10:38 AM
I have not observed aggression in groups I raised but that was done in large open tanks where all stayed together. The real cool differences between sunfishes is with respect to larval and fry behaviors and some of that does involve associations with cover which also has a powerful age / size component for early developmental stages.
#10
Guest_Skipjack_*
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Posted 14 July 2014 - 01:20 PM
What is the deal with dwindling from ingesting Artemia cysts that you speak of? I am totally unfamiliar with this.
#11
Guest_centrarchid_*
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Posted 14 July 2014 - 02:22 PM
Digestive tract either clogged or scarred by cysts passing through. Growth rate is greatly decreased with metamorphosis effectively stopped and mortalities may take a couple of weeks with rates very high approaching 100% for stunted individuals. Very young larvae do not appear to consume cysts even when present but once they are about the age we begin feed training (second week) the larvae are then inclined to eat the cysts. Apparently a single bad harvest allowing cysts into a brood tank within the window of vulnerability can ruin brood. When looking at how things happen from a distance, you see the majority of the brood appear to cease growing then they start dying leaving only the larger fry. Removing the larger fry does not help smaller fry survival rate. Additionally the larger surviving fry do not grow as fast as average fish in broods not so effected even when other broods of same spawn and reared in same system. Older fry can eat cysts without apparent problems. We routinely feed discarded cysts for female broodfish without issue.
We got a real handle on the problem when broods were broken up into batches where each batch was fed from its own brine shrimp harvest setup (treatment). For me, new student workers in the lab where strongly associated with improperly harvested brine shrimp and they could see the impacts first hand of being sloppy.
Harvesting brine shrimp involves more than what a simple reading of procedure indicates.
We got a real handle on the problem when broods were broken up into batches where each batch was fed from its own brine shrimp harvest setup (treatment). For me, new student workers in the lab where strongly associated with improperly harvested brine shrimp and they could see the impacts first hand of being sloppy.
Harvesting brine shrimp involves more than what a simple reading of procedure indicates.
#12
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Posted 14 July 2014 - 02:51 PM
Very interesting. I have fed a lot of brine shrimp. Guess I just got lucky and harvested them well enough, or my fry were large enough for it not to be a problem. Thanks.
Symptomatically sounds very similar to coccidiosis in ruminants.
Symptomatically sounds very similar to coccidiosis in ruminants.
#13
Guest_centrarchid_*
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Posted 14 July 2014 - 03:20 PM
Or coccidiosis in chickens. Plays out very similarly. Pathogen / parasite very likely in my opinion with fry.
#14
Guest_mikev_*
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Posted 16 July 2014 - 08:58 AM
Something like this.... (sorry for the crappy photo)
Yes, this seems to be the case indeed.... not sure this is a good thing at all, it seems that the growth rate accelerated once a fry ceases to behave like larva (not hiding=>eating much better), but this leads to some fry being 2x the size of others as I see now.
Regarding artemia cysts: they are not getting any. I tested this theory deliberately on rainbows and did not see any ill effects. Of course, it may be different for a different type of fish.
The real cool differences between sunfishes is with respect to larval and fry behaviors and some of that does involve associations with cover which also has a powerful age / size component for early developmental stages.
Yes, this seems to be the case indeed.... not sure this is a good thing at all, it seems that the growth rate accelerated once a fry ceases to behave like larva (not hiding=>eating much better), but this leads to some fry being 2x the size of others as I see now.
Regarding artemia cysts: they are not getting any. I tested this theory deliberately on rainbows and did not see any ill effects. Of course, it may be different for a different type of fish.
#15
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Posted 16 July 2014 - 11:24 AM
It is different for different types of fish. Bluegill, green, bantam and warmouth get hammered by sloppy cysts management while red spotted and longear are very tolerant.
Fish do appear to stall growth wise during metamorphosis, at least with respect to length. Depth and width still change a lot as well as all the morphological changes.
Fish do appear to stall growth wise during metamorphosis, at least with respect to length. Depth and width still change a lot as well as all the morphological changes.
#16
Guest_mikev_*
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Posted 16 July 2014 - 11:47 AM
Yes, this is very interesting indeed.... I raised quite a lot of fish (cyprinids, rainbows, corys, loaches, plecos, gobies etc etc) but never any kind of sunfish and they are decisively different. New experience... glad I got into this 
and sure you are right about length being stalled now, as other things happen.
and sure you are right about length being stalled now, as other things happen.
Edited by mikev, 16 July 2014 - 11:48 AM.
#17
Guest_mikev_*
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Posted 04 August 2014 - 08:26 PM
If I may ask: what is the appropriate food for them now?
Growing, still under 0.5" but much deeper bodied, fed with artemia and powdered food... would small bloodworms be safe? if not, what else?
Thanks
Growing, still under 0.5" but much deeper bodied, fed with artemia and powdered food... would small bloodworms be safe? if not, what else?
Thanks
#18
Guest_centrarchid_*
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Posted 05 August 2014 - 09:28 AM
Get a smaller granule feed like used to smaller tetras. Make certain it is fresh. To expedite training process, mix a little with a concentrated solution of freshly hatched brine shrimp immediately prior to feeding. Do that for a week then stop mixing. I would still give them brine shrimp until you are confident they are trained over to pellets.
#19
Guest_mikev_*
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Posted 06 August 2014 - 10:30 AM
Thanks...
No intend to stop brine shrimp, only the feeling I should start supplementing. They do take powder (Sera) but again this is too small a food now.
What about things like frozen daphnia?
No intend to stop brine shrimp, only the feeling I should start supplementing. They do take powder (Sera) but again this is too small a food now.
What about things like frozen daphnia?
#20
Guest_centrarchid_*
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Posted 06 August 2014 - 11:18 AM
They should consume frozen daphnia.
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