# NPT 5 - Cory Hatchery



## Dustymac (Apr 26, 2008)

With all the green cory eggs getting regularly deposited in the 55 gallon tank, I thought it might be interesting to see if they couldn't be hatched and raised without too much trouble. I've had a spare 10 gal left over since getting rid of the mbuna, so here is the NPT hatchery about one week old:










The 50+ eggs are suspended in the plastic transfer tank so they're safe from snails. A trickle pump pushes about 2 gallons per hour from the air stone into the transfer tank. For plants we have a broadleaf anubias, a tiny bronze crypt and a couple ludwigia repens over in the right corner. Some Frogbit and Duckweed circle overhead. It's important not to clutter up the landscape to see if any eggs hatch and how the fry are developing. We'll add more plants as the fry grow!

The substrate is new for me and I wasn't sure what would be best for the baby cats, deciding gravel might be too coarse. I went with Miracle Grow garden soil since it was already in the shed, and topped it with about 1/2" of play sand (also in the shed). The Anubias and Frogbit have already responded quickly to the new digs.










Above - A new shoot from the Anubias.










Above - a kinda cool pic of the rhizome. Where it butts into the sand is where it was pruned. The two hanging roots have grown about 3/8" since planting. I realize most fry are raised in bare, sterile tanks or concrete ponds - it's how I've always done it. I hate to count my catfish before they hatch, but could it be that NPTs are best for raising fish, too? Wish us luck! 

Jim


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## dwalstad (Apr 14, 2006)

This tank looks like fun!

I think NPTs are _perfect_ for raising small numbers of baby fish at a leisurely pace.

Soil is particularly rich with bacteria. Protozoa and other little critters feed on the bacteria, so the substrate is rich with natural food. You really don't even have to feed the babies when they're little. Plus, the plants keep the water and substrate pure, so you don't need a filter.

Attached is photo of my Bettas when they were little, about 1/4". You can see them picking up stuff out of the substrate. I have raised about 24 in a 5 gal tank. Then went through a stage where they were grossly overweight such that they would roll around at the top of the tank (these fish are really pigs). I thought they were diseased, but it turns out I was just feeding them too much.

I put them on a diet.  Now, they're doing quite well, and I'm looking to cull a few and put the remainder in a larger tank.

Good luck with your Corys!


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## Dustymac (Apr 26, 2008)

Thanks Diana,
You're right - this is lots of fun. But I think I screwed up. A day after putting the eggs in the hatchery all but two were covered with fungus. It's been so long since seeing fungus in my tanks, I'd forgotten about the white hairy stuff and how much it likes fish eggs. Anyway, I came up with two possibilities:

1) All the eggs but two were damaged when removing from the parent tank, leaving them susceptible to the fungus.

2) The new NPT is teaming with fungal spores and it was dumb luck that two eggs were spared.

I'm sorta leaning towards the latter but we'll know for sure after the next batch of eggs. Fortunately the healthy eggs hatched and there are two baby corys in the transfer tank. It's funny how they behave so much like their parents: long periods of inactivity punctuated by short bursts of bee-bopping all over the place.

And you couldn't be more right about the abundance of microlife. I've spotted a nematode squiggling through the water, some planaria crawling on the glass and varietal protozoa. But the strangest interloper dropped in from the tank next door - one of the big Apple snails. It was scooting across the bottom yesterday morning. These guys wander around so much, I'm wondering if they can be fitted with GPS tracking collars? 

Jim


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## Dustymac (Apr 26, 2008)

Just a quick update...

The two baby Corys are doing fine, about an inch long. Oddly, one is really dark and the other is nearly transparent. I recently added about 17 half-sibling fry and they have disappeared, probably food for the two older catfish.

I'm not liking the sand substrate very much. The mulm stays on the surface and gets stirred up by browsing. I'm thinking of siphoning most of it out and laying down a layer of gravel. Any thoughts?

Jim


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## dwalstad (Apr 14, 2006)

Dustymac said:


> I'm not liking the sand substrate very much. The mulm stays on the surface and gets stirred up by browsing. I'm thinking of siphoning most of it out and laying down a layer of gravel. Any thoughts?
> Jim


Mulm is filled with protozoa and other little critters that fish and their babies can feed on.

I've heard that Corys do better with a sand substrate?? Long, long ago I kept a few Corys with a gravel overlayer, and the fish lost their whiskers.


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## Dustymac (Apr 26, 2008)

I had the same thing happen in one community tank. The gravel was 1/4" quartz and the Cory's whiskers turned into nubbins. But all the other tanks - a couple dozen at least - a softer, more rounded gravel had no ill effects.
That said, lots of people like sand while this is my first experience with it. Am I the only person who prefers gravel?

Jim


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## aquabillpers (Apr 13, 2006)

No, I prefer gravel too, the 2mm to 3mm size.

The mulm does build up on the sand because it is too fine to allow the mulm particles to get to the lower part of the substrate.

Cory breeding tanks are perhaps different. One authority in the 1940's - (Innes?) - reported that some cory breeders used boiled oatmeal in breeding tanks. The fry disappear into it and emerge several weeks later.

Bill


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## baos (Jul 3, 2009)

dwalstad said:


> Mulm is filled with protozoa and other little critters that fish and their babies can feed on.
> 
> I've heard that Corys do better with a sand substrate?? Long, long ago I kept a few Corys with a gravel overlayer, and the fish lost their whiskers.


And with the whiskers their ability to reproduce


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## NatalieT (Mar 20, 2007)

aquabillpers said:


> Cory breeding tanks are perhaps different. One authority in the 1940's - (Innes?) - reported that some cory breeders used boiled oatmeal in breeding tanks. The fry disappear into it and emerge several weeks later.


I once read something similar, but it called for a thick layer of mulm (I think it said 1/2" or more). It said that the fry "disappear into the mulm...." (and reappear later.)

Now if I could just remember what book it was in so I could re-read it..... It's been 15 years and I no longer live near the library that had that book.


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