Slow Growth Rate ~ Peacock Gudgeon Fry

[RCA]

I am finding despite feeding well, my fry seem to be growing at a very slow rate. I have read this is the case, yet cannot find any hard facts out there. Thus I am looking for others with experience of breeding these fish to please advise. How long does it take them to grow?

You can see them in my previous topic linked below.
http/www.fishforums.net/index.php?/topic/437197-peacock-gudgeon-journey-of-the-fry/

 

[eaglesaquarium]

How often are you changing the water, and what volume are you changing? I don't have experience with grudgeon fry, but with any fry, you want to change the water frequently and in fairly large percentages.

 

[RCA]

Is that because the stronger ones release a hormone that stunts the growth of the weaker ones, thus you need to ensure it gets taken out? I had also read that PG are sensitive to changes and to only do small water changes. Any advice welcome, as they just do not seem to be growing very fast.

TBH I have been dealing with a lot personally and thus have focused more on ensuring the main tanks are done. The fry however do get about a 20% change every other week or sooner if I have the equipment out.

 

[eaglesaquarium]

I believe the hormone is a very likely explanation for the slowed growth.  
 
20% biweekly isn't really the best plan for fast growth of fry.   I understand the 'sensitivity' issue with the fry, but if you have been keeping up with water changes prior to their birth, then the tap water is pretty closely matched to their tank water... and so water changes should not actually be a shock to them in any way.
 
 
I'd suggest that 20% twice weekly would be more appropriate, but like I said, I haven't dealt with gudgeon fry in particular, but am speaking more about fry, in general.  
 
 
 
Just for the sake of discussion, Ian Fuller (aka 'Coryman), an ichthyologist of particular renown on the corydoras species suggests that fry grow out tanks should have 50% water changes daily, if not twice daily.  He suggests using water from the main tank, rather than tap water to be used...  and that makes a lot of sense, given that it is probably closest to the water that they were hatched (or at least spawned) in, and where they will be going.  This water will be free of the growth inhibiting hormone, free of chlorine, and the pH will have stabilized from any other gassing off processes that may need to take place.
 
http/www.planetcatfish.com/forum/viewtopic.php?t=8726
 
 
 
So, it might be worthwhile to do a couple tests on your main tank, versus the fry tank... and compare their values.  If they are fairly close, you could probably use water from the main tanks and not worry as much about shock for the fry.

 

[RCA]

Many thanks eagles..., will start to do this, however, do you think they will improve their growth rate by doing so, or will they remain small now?

The father was removed from the main tank with the eggs, and a smaller tank set up for this purpose, it originally had water from the main tank along with conditioned water. I have also used conditioned water to do the previous water changes, yet it makes sense to take it from the main tank. I will test the water, however may do a 70/30 tank/conditioned water in the changes so the main tank does not get affected too much as well. It is a 30L aquarium which has always been a breeding ground for fish in there, thus I do not want to mess it around too much. I am reluctant to take from my other aquariums as I sadly had a bad incident in one of my tanks, and now keep them all as independents as we never know what may actually be lurking within them!

 

[eaglesaquarium]

Keeping the systems separate is a smart move... but the fry came from the tank where dad is now, so there has already been some crossover.  No reason not to continue with that until they are grown.  The breeder can always be sanitized after the fry are moved out.
 
 
Regarding the growth rate... I haven't a clue as to how their growth will rebound.  Sorry.  

 
 
I think one of the thoughts behind the use of the main tank as the source of their 'new' water is that any chemicals (such as dechlorinator) will be inert and/or so dilute that it should have minimal effect on the fry.   Whereas adding direct tap water, even with conditioner, may have some free chlorine (even for a brief moment) or a slight overdose of dechlorinator, etc.  Better safe than sorry... also the temp will be almost a perfect match.  And this will force you to do more water changes on the larger tank at the same time, so that nitrogen won't be building up in either tank.  
 
A 30L tank would be getting roughly 15L of 'fresh' water once or twice a day, which means that the main tank would also be getting 15L of tap water to replenish its supply.  Ultimately, this will keep all the waste products down in both tanks.  
 
 
Best wishes with this, and let us know how this progress.

 

[RCA]

Thanks again Eagles. Just so I am clear it is the main tank that is 30L, the breeder setup is somewhat smaller, not sure exactally the size at this stage. The main tank also runs an external filter so there is a high turnover. I have started the process and used a turkey blaster to assist in cleaning the bottom of the breeder.

I came across the following articles to assist with my understanding, worth a read:
http/www.monsterfishkeepers.com/forums/archive/index.php/t-62030.html

http/forum.simplydiscus.com/archive/index.php/t-21312.html

 

[RCA]

A quick update: in the end I moved the fry to a breeder box that took water from the main aquarium. This was as I was unable to do the regular water changes for sometime due to personal reasons I felt it was best for the remaining fry, of which there were not as many as I would have hoped. Eventually there were none left in the box, until one day I spotted one, inside the main Juwel 180, which also at the time housed some Panda Cichlids! It appears, that it must have initially gone through the grill on the fry box into the main tank. I therefore caught it and placed it in with my Celeste Danios for awhile. Then a few days later I spotted another yet decided to leave it in the heavily planted Juwel. They both have now grown to about 2.5cms, and now both live in the Juwel. I am not convinced if they will grow much larger having been that size for some time now!

Any thoughts...?