Sorry for the long post, but let me throw out some general information and see if anyone has any explanations as to why I'm still losing fry.
Right at about 2 months ago my Rainbow shiners bred and I ended up with ~100 free-swimming fry. The adults were removed and the fry had a ~40 gallon tank to themselves. The tank was kept around 80F. Water parameters have been checked every other week and the tank has been good the entire time, (no Ammonia/Nitrites, pH ~8, Alkalinity around 100). All seemed to be going well for the first few weeks. They were being fed newly hatched artemia and rotifers twice a day and were growing quickly.
After a few weeks I did notice little white spots on the tiny fish (likely ich) and I added salt (b/t 4 and 5 ppt) and within a week or so they were all clear. *Mind you I didn't notice many IF any deaths due to this outbreak as I caught it early when only a couple of them were seen with the spots. I decided to leave the salt on for a few weeks as there were no adverse affects.
As the fry continued to grow I started adding crused flake to their diet, in addition to cyclopeeze, daphnia, and minced blackworms. There was a period of a few days where the heater was unplugged and the tank dropped to ~65F. This also did not appear to affect the fish.
Since all that, I now only have about <20 fish. They are still getting fed twice a day, temp is still around 80, and the water quality is still good. The only thing I can think of since I am ruling out: inadequate amount of food, temps, water parameters, and lack of predators,... is the powerhead. There has been a powerhead in the tank the entire time. (It was for the adults, but since it was still on when I noticed the fry I left it in). They did find and stay in a corner with reduced flow, but I didn't start losing a significant portion of them until a week or two ago once they were significantly larger @ ~3/4". When thew were about a week old and gained some strength they actually started "playing" in the current. Does anyone else remove all sources of major current when rearing fry? Being a stream fish I don't feel that it is a huge issue as long as they have an area of reduced flow, which mine do. Note: they are not getting sucked into the intake as the pump is attached to an undergravel filter.
They've been looking fairly thin, and don't seem to "play" in the current as much. I still see their bellies turn pink after eating some artemia, and they do eat other foods as well. I still rule out an inadequate amount of food because I often see artemia still blowing around in the current the following morning. I had the ability to have someone perform as much of a "necropsy" as possible on one of these little guys that died to see if there were any parasites in the gut. None were found, but that would have made sense if there were.
I'm contenplating turning off the powerhead as it is the only other thing I can think to change. Any idea(s)?
Thanks.
Rearing Fry
Started by
littlen
, Jul 16 2010 12:58 PM
17 replies to this topic
#2
Guest_PhilipKukulski_*
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Posted 16 July 2010 - 08:33 PM
Ideas:
To be safe, remove the powerhead
and add a sponge filter.
Check for hydra.
Lower temp to 74F.
Could be Velvet disease - not easy to treat for without killing the fish. Malachite Green.
50% water change every week with aged water of the same temperature.
Electrical short on the powerhead?
Feed only crumbled flakefood and live baby brine. Pre-treat brine shrimp cysts for each batch with 2 drops chlorine laundry bleach per liter of water (assuming 1/4 cc of cysts.)
To be safe, remove the powerhead
and add a sponge filter.
Check for hydra.
Lower temp to 74F.
Could be Velvet disease - not easy to treat for without killing the fish. Malachite Green.
50% water change every week with aged water of the same temperature.
Electrical short on the powerhead?
Feed only crumbled flakefood and live baby brine. Pre-treat brine shrimp cysts for each batch with 2 drops chlorine laundry bleach per liter of water (assuming 1/4 cc of cysts.)
#3
Guest_centrarchid_*
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Posted 17 July 2010 - 10:28 AM
Make certain unhatched brine cysts and shells not getting in with fish. This can sometimes be a problem with older fry. Problem can also be a function of brine cyst used. Cleaning / treating with chlorine as Phillip recommends usually fixes latter problem.
Make certain brine shrimp are freshly hatched.
Again stress water change with aged water.
Keep lights on at all times. Do not know why works.
Make certain brine shrimp are freshly hatched.
Again stress water change with aged water.
Keep lights on at all times. Do not know why works.
#4
littlen
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Posted 17 July 2010 - 10:19 PM
They have been getting 24 hour old, decapsulated, brine shrimp the entire time. Lights are on about 8 to 10 hours a day. I'm down to about 7 fish. I turned the powerhead off. I watched the remainders feed today--again noticing their bellies turn pink/orange after they've had their fill. But if nothing changes at the rate they've been dying off, this thread may be over shortly....
Nick L.
#5
Guest_centrarchid_*
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Posted 18 July 2010 - 09:10 AM
Nick,
Do not give up just yet. You might give following extreme measure some consideration.
Setup a bare 10 gallon aquarium with a sponge filter, preferably from tank already in use. Fill half full with water from tank holding rainbow fry. Very carefully transfer fry from old tank into 10 gallon. Then top off 10 gallon with aged water (slowly over hour or so). Hopefully you will have left unknown problem behind. Keep lites on and do water changes.
You say brine shrimp 24 hours old. How many times a day to you start a brine shrimp hatching jar?
Do not give up just yet. You might give following extreme measure some consideration.
Setup a bare 10 gallon aquarium with a sponge filter, preferably from tank already in use. Fill half full with water from tank holding rainbow fry. Very carefully transfer fry from old tank into 10 gallon. Then top off 10 gallon with aged water (slowly over hour or so). Hopefully you will have left unknown problem behind. Keep lites on and do water changes.
You say brine shrimp 24 hours old. How many times a day to you start a brine shrimp hatching jar?
Edited by centrarchid, 18 July 2010 - 09:11 AM.
#6
littlen
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Posted 19 July 2010 - 07:47 AM
New brine are started every morning. As I mentioned before, they are decapsulated and fed twice a day to the fry--around 8am and 4pm. I have added a light to stay on for 24hrs and will do a w/c more frequently. 6 are left....fingers crossed. Thanks for the suggestions.
Nick L.
#7
Guest_centrarchid_*
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Posted 19 July 2010 - 01:24 PM
Problem possibly with brine shrimp harvesting regimen. Harvest / feeding in morning fresh while PM feeding with older nauplii. Older nauplii held at high densities are less nutritious and likely to harbor more disease causing organisms. Based on what we are seeing, using 12 hour post hatch nauplii may cause health problems even in more advanced fry. Appears to do so in our sunfishes.
I reccomend having one jar that is initiated and harvested in morning and another setup for PM. Why feeding at 4 PM? COuld second feeding be moved to 6 or 8 PM?
I reccomend having one jar that is initiated and harvested in morning and another setup for PM. Why feeding at 4 PM? COuld second feeding be moved to 6 or 8 PM?
#8
Guest_gerald_*
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Posted 19 July 2010 - 04:31 PM
Can you see ANY other symptoms in the sick ones besides being thinner and less active in current? Any skin or eye cloudiness? color change? labored breathing? swelling or reddening around anus, nostrils, or base of fins? clear or white stringy feces? Body sores, bumps or deformities (spine, jaws or gill covers not closing, limited fin mobility)?
Besides nutrition and electric leakage, I'm wondering if there might be some kind of poisoning from something in the tank or something drawn into an air pump, or possibly some slow-progressing internal infection, bacterial or viral. Is your water very soft? If so, adding some rift lake cichlid salts might help if ion deficiency is part of it. (pH and alkalinity measurement will not tell you whether Ca, Mg, K etc are sufficient)
Besides nutrition and electric leakage, I'm wondering if there might be some kind of poisoning from something in the tank or something drawn into an air pump, or possibly some slow-progressing internal infection, bacterial or viral. Is your water very soft? If so, adding some rift lake cichlid salts might help if ion deficiency is part of it. (pH and alkalinity measurement will not tell you whether Ca, Mg, K etc are sufficient)
Edited by gerald, 19 July 2010 - 04:35 PM.
#9
littlen
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Posted 20 July 2010 - 12:21 PM
I could space out the feedings a little more, but the problem still persists. I am still offering other foods as well. But with everything I put for them to eat, I notice them mouthing the food more often than ingesting it. This includes the artemia.
At 3/4" it's hard to clearly see if their are any physical abnormalities. Other than being thin, they look like juvenile rainbow shiners. (The bronze coloration is starting to develope).
I have raised and kept many other species in this same tank without any issues. I've checked for stray electrical currents and found none. I will also check the Ca level.
As I metioned a few posts back, no 'gut bugs' were found in one that recently died. I would have liked to have found something so that at least I could have an angle to attack. But I'm still in the dark. The parents were wild caught and had various external parasites that were treated with a Formalin bath (125ppm for one hour). But as I also mentioned in my original post, they fry came down with ich a few weeks after they became free-swimming. So it is likely that other 'things' survived.
At 3/4" it's hard to clearly see if their are any physical abnormalities. Other than being thin, they look like juvenile rainbow shiners. (The bronze coloration is starting to develope).
I have raised and kept many other species in this same tank without any issues. I've checked for stray electrical currents and found none. I will also check the Ca level.
As I metioned a few posts back, no 'gut bugs' were found in one that recently died. I would have liked to have found something so that at least I could have an angle to attack. But I'm still in the dark. The parents were wild caught and had various external parasites that were treated with a Formalin bath (125ppm for one hour). But as I also mentioned in my original post, they fry came down with ich a few weeks after they became free-swimming. So it is likely that other 'things' survived.
Nick L.
#10
Guest_centrarchid_*
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Posted 20 July 2010 - 08:54 PM
Nick,
Your fry maybe surfuring from what I call the dwindles where cause not known. Some stressor impacted fry / larvae early on resulting in survivors being unable to recover fully. Result is the numbers keep going down, they do not feed up regardless of feeding regime used. When this problems hits one of my broods, it is terminated and parents setup to re-breed.
Your fry maybe surfuring from what I call the dwindles where cause not known. Some stressor impacted fry / larvae early on resulting in survivors being unable to recover fully. Result is the numbers keep going down, they do not feed up regardless of feeding regime used. When this problems hits one of my broods, it is terminated and parents setup to re-breed.
I could space out the feedings a little more, but the problem still persists. I am still offering other foods as well. But with everything I put for them to eat, I notice them mouthing the food more often than ingesting it. This includes the artemia.
At 3/4" it's hard to clearly see if their are any physical abnormalities. Other than being thin, they look like juvenile rainbow shiners. (The bronze coloration is starting to develope).
I have raised and kept many other species in this same tank without any issues. I've checked for stray electrical currents and found none. I will also check the Ca level.
As I metioned a few posts back, no 'gut bugs' were found in one that recently died. I would have liked to have found something so that at least I could have an angle to attack. But I'm still in the dark. The parents were wild caught and had various external parasites that were treated with a Formalin bath (125ppm for one hour). But as I also mentioned in my original post, they fry came down with ich a few weeks after they became free-swimming. So it is likely that other 'things' survived.
#11
littlen
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Posted 02 August 2010 - 07:23 PM
Just an FYI for all those who have been following. I added a light to stay on the tank 24/7 and it seems the slow die-off has stopped. There are 5 left and they seem healthy and their bellies remain full. Don't know how or why this happened--too many factors to sort through. Anyone want to chime in possible explanations as to why the light could have helped? I have reared many species of fry (non-native I have to admit) and never left lights on all the time and had success growing out 80% + of the offspring.
Thanks everyone.
Thanks everyone.
Nick L.
#12
Guest_centrarchid_*
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Posted 04 August 2010 - 12:18 AM
Yes, too many factors. You might have even been through worst without following suggestions.
If light was savior, then it maybe that when your lights went off the fry could not see well enough to feed or avoid obstacles like tank walls and filter intakes. Species may vary in terms of how well they can respond to low light levels in a tank. Also your exotics may have been through multiple tank reared generations and been hatchery selected to be more tolerant of tank conditions. Could go on and on with could be's.
If light was savior, then it maybe that when your lights went off the fry could not see well enough to feed or avoid obstacles like tank walls and filter intakes. Species may vary in terms of how well they can respond to low light levels in a tank. Also your exotics may have been through multiple tank reared generations and been hatchery selected to be more tolerant of tank conditions. Could go on and on with could be's.
#16
Guest_centrarchid_*
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Posted 09 August 2010 - 09:21 AM
Nick,
Your fry, if they survive through adulthood should prove excellent for effort next spring. Keep posting their development. Such record keeping keeps me on toes regarding what husbandry methods do and do not work.
Your fry, if they survive through adulthood should prove excellent for effort next spring. Keep posting their development. Such record keeping keeps me on toes regarding what husbandry methods do and do not work.
#18
Guest_MAZUREL_*
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Posted 07 October 2010 - 02:09 PM
I raised 30 young rainbow shiners this season in a 40 gallon tank, in the Netherlands, may-be 100 young to much to try to raise in a 40 gallon tank?. My yong fish are 4 cm already , 7 okt ,not one died, and not a single one has become ill. Even the one who could not eat properly because the mouth is a little disvormed. When they grew over 3 centimeter, i made 3 groeps of 10 fish each groep their own tank of 20 - 40 gallon.
I raised in the past I raised Rasbora heteromorpha, had in a 40 gallon tank over 200 young, the young fish did not become ill, but blue algae made the water dirty, than I had to take the young fish out, to prefend they become ill. I hope this information can be useful.
I raised in the past I raised Rasbora heteromorpha, had in a 40 gallon tank over 200 young, the young fish did not become ill, but blue algae made the water dirty, than I had to take the young fish out, to prefend they become ill. I hope this information can be useful.
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