Piotr K.
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> 1. How often did you feed them?
Twice a day, sometimes three times a day.
> 2. What temperature did you keep the water, how often did you change it?
22-24 C deg, I usually make about 30% water changes twice a week, but recently I had no time at all, so I didn’t make any water changes for a month or so
Still, NO3 levels are not going higher than 25-50 mg / liter (JBL 6in1 test stripes)> 3. Was your substrate light or dark in color?
All substrates except “old fine gravel” are light. Not white, but rather yellowish, sort of
> 4. Did all tanks have the same lighting? If so what was the light and how many hours per day was it on?
Each tank has a 1W LED module over it. The lighting is turned on during 1:30PM-9:45PM, plus the daylight coming from the window.
> I appreciate you posting your tests. its inspiring me to try some of them as well.
Do it, that’s the only way to know something for sure.
> Any chance you have some photos of your breeding setups?
No problemo, but gimme some time
In my experience, it’s not possible to condition CPDs like Danio rerio – after sevaral days without males females start to die. It seems that tbey need to get rid of the eggs on a constant basis. So I “condition” them putting the desired set of fish together (like 2M+3F) in the breeder tank, and feed them a lot of live food (bloodworms, “glassworms” [not sure what’s the English name], adult artemia, newly hatched artrmia nauplii).
No, I didn’t try bare bottom, because IMHO it doesn’t make any sense – without substrate the eggs are exposed for being eaten (the same as on fine sand, in fact), and there is no filtration provided by the substrate.
“What did you feed time?” – what does it mean? How often do I feed…?
OK, here it is – I decided to post a whole table with the results
These data are for just one “breeding run”, i.e. adult fish were kept in each tank (aquarium / plastic container) for 3-4 weeks or so, and then removed to another set of 18 containers (all being the same, for a change). After few days fries started to appear, and the numbers I present in the table are derived from today’s counting – after about 3 weeks since the removing of the parents.Conclusions: At the moment I can’t see any clear pattern depending on the substrate; most fries are originating from coarse/mop, coarse/moss and sand/mop combinations, but this very well might be due a pure chance. One thing for sure is that there are far more fries from plastic containers (Px) (25 on the average) than from aquariums (Ax) (7 on the average) – I have no idea why, maybe it’s the area of the bottom (plastic containers are lower and wider), maybe it’s something else… This is why I will make at least one more run in exactly the same combination, to see if there will be any significant differences in the frequencies of fries.
If there is any statistician among you guys here, you’re welcome to make some calculations on these data – I’ll try to make some, but I’m not an expert on this
Looking forward to your comments / questions 
Explanations:
Tank (all are about 25 liters):
Ax – Aquarium number x
Px – plastic container number xBottom (type of substrate on the bottom of the tanks):
sand – fine sand
fine – fine gravel (about 2-3 mm diameter), 100% quartz
old fine – my old fine gravel (about 2-3 mm diameter), mixture of various rocks, raises pH and GH slightly
coarse – coarse gravel (6-8 mm diameter), 100% quartzSubstrate (type of spawning substrate):
moss – java moss, covering almost whole bottom
mop – mop of acrylic wool, 150 “circles”, length about 20 cmmales, females – pretty obvious, letters A, B and C denote different sources of fish
fries – number of fries counted
Sorry, I’m still working on the newest video, it’s quite difficult and time consuming to make the commentary… (I run internet aquarium television, BTW: http://www.youtube.com/DefiniteAquascapeTV), but I promise I’ll post the results today
(it’s April the 10th in Poland ).Today is the last day of my work, the hectic period is almost over
I have to count all the fries in various tanks, I should post the info till the end of the week Some fries do get these issues even when undisturbed. It’s either genetic defect or problem caused by some environmental factors (too low temperature…?), and I wouldn’t worry about it too much. In the wild there is never 100% fully healthy progeny, some are stronger some are weaker, that’s life
My tests are still under way, however I already have some very interesting results
I’ll post them ASAP, the problem is that at the moment I don’t have much time… (was working on the fishroom, relocating CPDs from 18 tanks to another 18 tanks, setting up the latter, and in the meantime quitting my job at the Uni and starting my own company ).Be back soon
Hey, GREAT!!
So the mesh seems to be the right size! (as long as the eggs didn’t fall down through the gap between the mesh and the wall of the trap). BTW – what is the exact size of the “eyes”? Can you measure it?@BallAquatics wrote:
They are small as adults so they don’t appear to grow in size like fry from larger fish do. If you think about it thought, they are sexually mature at 12 weeks old so really they are growing very fast… they just never get very big!
That’s what I thought when I wrote “grow up” – reaching sexual maturity, not an absolute size of the fish. I know CPDs become sexually mature very fast – comparing to harlequin rasboras, which are ready to sell after at least three months of intensive rearing, for example (I know a guy who is breeding them commercially).
@BallAquatics wrote:
You are correct though, I think the D. erythromicron grow slower than CPD’s.
OK, thanks for all the infos
I have so many tanks at the moment that sooner or later I will also try to test if the slower growth ratio of erythromicrons (=longer time to reach sexual maturity comparing to CPDs) is caused by wrong food (infusoria cultured on dry banana leaf) or by some conditions being not right (maybe water changes too seldom…?), or if it’s just their nature… I find it quite strange that it takes them twice as long to reach sexual maturity, as both species are so closely related…@shift wrote:
Do you guys have photos of your setups?
As promised, photos of two of my breeder tanks. The upper one is with fine gravel and mop, the lower one is with coarse gravel and moss. Sponge filters are attached to the back wall, that’s why it looks as if the upper filter was attached to the mop
(in fact, it’s well behind the mop). Tanks are 23x23x43 cm, photos taken through the 23×23 cm walls.
Dennis, thanks for the details, your schedule seems to be very good for getting healthy fish!
One question, because I’m not sure if I understood correctly:@BallAquatics wrote:
First time breeders usually produce 15 to 25 fry per set-up and top out at 75 to 100 per set-up. If I had to pick an average I say 50 to 65 fry. That’s how I come to use 20 gallon grow-out tanks.
These numbers are for one breeder tank per one week, right?
Aha, and one more question – I see you have D. erythromicron as your avatar. Do you breed them, too? If yes, what’s the growing speed of the fry, comparing to CPDs? My experience is they grow two times slower than CPDs.
Hey, the first layout is amazing!
Is it Fluval Edge? Are the plants growing so nice under such weak light? Wow! As for the setup for the first attempt – it must have been a struggle to catch the adults in such densely planted aquarium… :mrgreen:
As for the setup for the second attempt: 1. The mesh size (the “eyes” of the mesh) is too small IMHO, it should be about 3-4 mm (not bigger, because adults, when scared, can easily get stuck in it) 2. I’m not surprised that the number of fry was smaller. You know why? Because the mop is a hanging one, so the spawning looked like this – the fish spawned in the mop, the egg fell down OUTSIDE the mop, and landed on the mesh; it didn’t go through the mesh, because the “eyes” are too small, so adults ate almost all the eggs (that’s what I think). Generally, CPDs breed in plants/mops, but the eggs are not adhesive and fall down – therefore the best mop is a mop which is laying on the bottom, not a hanging one.
The picture of the mop, bare bottom and a rock on the left side – the same situation, mop is hanging, and it doesn’t even touch the bottom. So, every egg which is laid within the mop will fall down, right onto the glass, where it will be easily found and eaten by the adults. Mops must lay on the bottom, or at least touch the bottom when hanging.
Egg trap – think like a fish: if given a choice between spawning within all the plants, and spawning in an artificial “grass” made of wool, what would you choose?
Egg traps don’t make any sense if you have other plants in the tank, cuz CPDs will breed in the plants, not over the trap. Second problem – the “eyes” of the mesh are IMHO too small, so no egg will fall through them. Eggs of CPDs are pretty big for such a small fish, about the size of the eye of CPD.I’ll post some pics tomorrow, as the lights over my tanks are off now (it’s 10:15PM here in Poland
)@shift wrote:
Well the parrents have been removed from the mesh bottom/mop experiment for a little over a week. saturday i spotted 3 fry, today i’m up to about 5… so it didnt work nearly as well as i hoped.
Hey, do you have a picture of your setup? Then we’ll see what we are talking about
@shift wrote:
I build an egg trap version of the mop and placed it into the shrimp tank with 2f/2m in it.. to see what happens
I’d do it like this – setup a 5.5 gal tank with coarse gravel and lots of moss, put your fish there, wait for a week, remove them, wait with patience another week-2 weeks to check if there are any fries. Repeat it at least twice, to see what the fish are able to produce in optimal conditions (and I’m pretty sure at my level of CPDs-breeding knowledge that a coarse gravel tank with moss is the optimal setup – I was even more convinced by what Dennis wrote recently
). In my opinion there is no need to use mesh bottom when using a mop – simply because the eggs stay in the mop, they don’t fall down (at least in my mops). Another thing which you could do (and which I did many times) is to remove the mop itself after a week, shake it into any small container with water, and see if there were any eggs inside.@shift wrote:
Piotr K. – 1000/month! damn you must have one big grow out tank!
Mate, I have about 50 tanks at home
Six growers altogether, about 100 liters each. I do not grow all the fries in one large tank!Dennis, what do you do with the fry after removing the parents? I mean, do you keep the fry in the tank, feeding them and waiting till they grow to ready-to-sell size, or you remove the fry to another tank?
Keeping fry in the breeder has one advantage – one doesn’t disturb the fry, and two disadvantages – the breeding tank is blocked as long as the fry is there (=you can’t breed adults again as long as the fry is there), and the volume is a little bit small for raising the fry to the ready-to-sell size (the bigger the tank the faster the fish grow, and the more stable are the conditions). The trade-off would be to wait for the fry grows a bit (say, 3-4 weeks), and then transfer them to a larger “grower” tank (still, the breeder is blocked for 4-6 weeks [1-2 weeks to complete hatching + 3-4 weeks for growing]).
Removing the fry has one advantage – removing the fry frees the breeder tank, so one can breed adults again there, and three disadvantages – removing tiny fry will take a lot of time if using plastic cup or “glass fry catcher”, netting them (which is definitely faster) might hurt them, and putting them to a larger tank with different conditions might also be stressful for them. But – one is able to collect dozens or even hudreds of fry in one large tank, which makes caring for them a lot easier.
I was also thinking about transfering the tiny fry to smaller tanks, like 1 US gallon, cuz it’s easy to fill such tank with the water from the breeder tank, and it’s easier to feed the fry during first days (high concentration of food in the water, the fry doesn’t need to look for the food – important for microworms, for example). After a week or two, when the fry reaches artemia-ready size, I’d transfer them to a larger “grower”. At the moment I’m not sure which will work best, so I’ll test everything
Another great way is to use egg traps – parents stay in one and the same tank, happy and undisturbed, and what is transferred is the eggs, which are not so sensitive as the tiny fry. Disadvantage – one is never certain if 100% of eggs were laid in the trap. This is why I want to test what the fry number will be when removing the parents from the breeder (100% of eggs are laid in the breeder, that is sure like taxes
), and compare it to the number of fry obtained when using the egg trap. Work in progress (I’m aiming for getting about a thousand of fish per month, this is why the differences begin to be important).Dennis, did you notice any changes in the eggs/fry number as the parents become older? And what’s your average fry number in the setup 5,5 US gallon with 1m+3f?
Best,
Piotr K.
