Do you cull?

[raven_wilde]

Out of curiosity, are people culling their fry as they develop? For example, eliminating fry with noticeable deformities. If so, what do you look for?

[BallAquatics]

I always cull any undesirable fish from a spawn. With CPD’s about the only thing I see are fish with swim bladder issues. It happens very rarely though.

Dennis

[plunket]

@BallAquatics wrote:

I always cull any undesirable fish from a spawn. With CPD’s about the only thing I see are fish with swim bladder issues. It happens very rarely though.

Dennis

Not sure if this is relevant but I found it interesting nonetheless…..
I recently had a conversation with an aquarist involved in commercial rearing of fry and mentioned that I’d had issues with an unusually high number of fish developing with deformed spines, and being unable to maintain position in the water column. Anyway, I asked him whether it was a genetic issue related to poor bloodlines or nutrition and he related an interesting insight. Apparently, high losses due to this phenomenon led to some close investigation of the issue. This led to the discovery that the thin oily slick caused by high-protein foods was preventing swim-up fry from being able to get to the surface to get the initial gulp of air required to fill their swim bladders. Apparently this process is critical as the air in the swim bladder provided the framework around which the spine develops and strengthens – without this support, the spine collapses, causing this deformity. I know that when I observed the issue with my fish, I was struggling to keep the surface of the tank clean and I’m convinced this may have something to do with it!
Anyway, I’m about to set up my breeding tank again and I can’t wait to see whether keeping the surface “slick free” has any effect on the number of deformed fish – will post my findings

[raven_wilde]

Huh, that IS interesting because the only real problem that I have noticed with my fry is spinal deformity… either a slight curvature or worse- usually they don’t live beyond a few weeks.

I have also observed noticeably curved spines in some of the adults that I have acquired from various sources. I had chalked it up to poor genetics but I suppose this could be just as valid an explanation.

What would be a good way to fight off the surface slime other than frequent water changes? Would increased surface agitation help?

[BallAquatics]

That is certainly an interesting theory Plunket. I feed fry mostly live foods and perform large daily water changes, so perhaps this is why I’ve seen swim bladder problems only on the rare occasion. I would think that a commercial breeder would also be doing massive daily water changes. Quality water is every bit as important as high quality foods, maybe more so.

Dennis

[plunket]

@raven_wilde wrote:

Huh, that IS interesting because the only real problem that I have noticed with my fry is spinal deformity… either a slight curvature or worse- usually they don’t live beyond a few weeks.

I have also observed noticeably curved spines in some of the adults that I have acquired from various sources. I had chalked it up to poor genetics but I suppose this could be just as valid an explanation.

What would be a good way to fight off the surface slime other than frequent water changes? Would increased surface agitation help?

Increased surface agitation would be one way, but the prevailing wisdom (and certainly my experience) holds that you really want to keep water movement to a minimum. I grow my fry in 30 litre cubes with an air-driven filter and the air turned down low – I would have expected the agitation from the air stone to be enough to break up any surface film, but last time I raised fry I did notice a build-up of surface protein. And of course, doing daily water changes doesn’t necessarily help because you aren’t draining water from the surface! Next time I see this film on the surface, I’m actually going to try and siphon it off using airline just below the surface. The other method is to use paper towel like blotting paper.
To be honest, although it doesn’t look good, I’d never worried about it before because my water parameters were good and I was still getting a good percentage of healthy fry! But it’s not fun having to euthanise deformed babies, especially if there’s a way to prevent it, and increase the yield per hatch

[plunket]

@BallAquatics wrote:

That is certainly an interesting theory Plunket. I feed fry mostly live foods and perform large daily water changes, so perhaps this is why I’ve seen swim bladder problems only on the rare occasion. I would think that a commercial breeder would also be doing massive daily water changes. Quality water is every bit as important as high quality foods, maybe more so.

Dennis

Hi Dennis
Sorry – should have said hello….it’s been some time since I was on the forum :oops:

I would certainly defer to your experience on the subject – I am a mere part-timer :lol:

Live foods are clearly better and cleaner, but I do supplement with liquid food just because it’s easier and always available. And would absolutely agree regarding clean water, and perhaps I can do a better job in this area. The commercial breeder I was talking too was actually doing experimental work on trying to establish a viable fishery for a type of salmon found in the South Atlantic, so the context was a little different. They had managed to manufacture a high-protein food that was effective in getting the fry to swim-up, but were then losing them due to this issue of excess protein build-up on the surface. Of course, changing their husbandry in this regard solved the problem. For me, it was just an example of how we sometimes mis-identify problems, and so miss the opportunity to fix them. In my case, I just assumed the percentage of deformed fish I was getting was down to poor genetics and too much inbreeding, when actually, it was poor husbandry on my part!

[raven_wilde]

When I was breeding I was feeding primarily live foods, although I would supplement with the finest grade of Golden Pearls. Since this was well over a year ago I cannot say for sure whether or not there was a surface slick.

I am getting my breeding set up going again though so when I get fry again I will be sure to keep an eye out for it and let you all know whether or not this seems to be an issue. I am always on the lookout for testable variables.

[plunket]

@raven_wilde wrote:

When I was breeding I was feeding primarily live foods, although I would supplement with the finest grade of Golden Pearls. Since this was well over a year ago I cannot say for sure whether or not there was a surface slick.

I am getting my breeding set up going again though so when I get fry again I will be sure to keep an eye out for it and let you all know whether or not this seems to be an issue. I am always on the lookout for testable variables.

Seems we are in pretty much the same place – I have 40 or 50 adult fish at the moment and although they are in fantastic condition, they are getting on a bit :wink: So, I’m about to pick out the best of them, possibly add a couple of females from a different bloodline, and get my breeding set-up going again. To be honest, I’d forgetten how exciting it was hatching my own fish, so can’t wait to get into it all again!

Good luck with your efforts – will look out for you on the forum

[raven_wilde]

You’re in a better position than I am – since I’ve only ever done this for my own enjoyment and on super small scale, I never really produced any huge batches of fry at once. After being too generous in giving away adults to other hobbyists and friends, a year-ish later I am down to about 5 of my original fry and a few of their parents (probably, I can’t tell them apart). Since healthy CPDs are difficult to come by up here I am kind of in a holding pattern until I can get some more contributors for the gene pool

[BallAquatics]

@plunket wrote:

Hi Dennis
Sorry – should have said hello….it’s been some time since I was on the forum :oops:

No need to be sorry. It’s good to see you back on the forum. A very interesting topic for discussion too.

@plunket wrote:

I would certainly defer to your experience on the subject – I am a mere part-timer :lol:

I’m certainly not trying to be the “expert” on the matter… just passing on methods that have worked well for me over the years.

My daily water changes are mainly to remove any growth inhibitor hormone and other unknown nasties that build up in fry grow-out tanks. I learned years ago, if you want strong uniform sized fry, you just can’t change too much water. If you read up on aquaculture methods, many farmers use what’s know as flow-through systems for this very reason.

I also feed lots of the Golden Pearls from the 5-50 micron size right up to the 500-800 micron size. It’s a fantastic feed in my opinion. I’ve never had any problems with it. I also feed lots of sinking pellets and wafers to fry once they reach about 1/2 inch in length. The Repashy gel foods are also a favorite of mine.

Dennis

[plunket]

@BallAquatics wrote:

@plunket wrote:

Hi Dennis
Sorry – should have said hello….it’s been some time since I was on the forum :oops:

No need to be sorry. It’s good to see you back on the forum. A very interesting topic for discussion too.

@plunket wrote:

I would certainly defer to your experience on the subject – I am a mere part-timer :lol:

I’m certainly not trying to be the “expert” on the matter… just passing on methods that have worked well for me over the years.

My daily water changes are mainly to remove any growth inhibitor hormone and other unknown nasties that build up in fry grow-out tanks. I learned years ago, if you want strong uniform sized fry, you just can’t change too much water. If you read up on aquaculture methods, many farmers use what’s know as flow-through systems for this very reason.

I also feed lots of the Golden Pearls from the 5-50 micron size right up to the 500-800 micron size. It’s a fantastic feed in my opinion. I’ve never had any problems with it. I also feed lots of sinking pellets and wafers to fry once they reach about 1/2 inch in length. The Repashy gel foods are also a favorite of mine.

Dennis

Hi Dennis
To be honest, I’d completely forgotten about the growth inhibitor factor! One of the changes I’ve introduced on my method is that I’ve invested in an RO unit – I was a bit concerned to find that my tap water TDI is over 300 so I’m going to try using RO for all my system water. Do you have an opinion on this? I’m also much better set-up to do water changes quickly and easily, having re-arranged my breeding set-up – before, it was just a tank on a pedestal in our spare room!
Just done a search on Golden Balls in the UK and found that there is an aquaculture business now offering them for sale here which is great news – am definitely going to try this, thank you. At what point do you start this feed?
I’ve never used wafers before, other than to feed my plecs and other bottom-feeders, so again, this is something I will try once I get to that point.
Can’t believe it’s so long since my last hatch – how time flies!

[plunket]

@raven_wilde wrote:

You’re in a better position than I am – since I’ve only ever done this for my own enjoyment and on super small scale, I never really produced any huge batches of fry at once. After being too generous in giving away adults to other hobbyists and friends, a year-ish later I am down to about 5 of my original fry and a few of their parents (probably, I can’t tell them apart). Since healthy CPDs are difficult to come by up here I am kind of in a holding pattern until I can get some more contributors for the gene pool

That is frustrating for you – generosity between enthusiasts is such a great thing in our hobby and sharing success and knowledge with like-minded people is just one of the many pleasures our hobby gives us, but not good if it leaves you with no fish to enjoy yourself :cry: Not to worry, I’m sure you’ll find some great fish soon and be able to build up your stock again – if you weren’t on the other side of the Atlantic I’d offer you some of my fish

[raven_wilde]

Thanks for the thought. There is a club auction coming up so I am hopeful I will find some. Otherwise I will likely have to order some.

[BallAquatics]

@plunket wrote:

One of the changes I’ve introduced on my method is that I’ve invested in an RO unit – I was a bit concerned to find that my tap water TDI is over 300 so I’m going to try using RO for all my system water. Do you have an opinion on this?

My water here is also very hard with a high TDS reading, but I use rain water rather than RO to soften it up a bit. For breeder set-ups, I often use a 19:1 ratio of rain water mixed with tap water. I always add just a bit of tap, even for my softwater plecos. The rain has NO buffering and will pH crash very easily. Just a splash of tap and all is good.

@plunket wrote:

At what point do you start this feed?

I normally feed the 5-50 micron size along with green water for the first 7 to 10 days. Once the fry are large enough to eat newly hatched brine shrimp I feed the bbs along with daphnia moina and sometimes micro worms. At around 30 days old, I move the fry into larger tanks and start feeding more prepared foods along with the live foods.

Dennis

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