fish purchase/Eat Their Young

[Dan Ponton]

I just tested my water for Nitrates for the first time.

Nitrites tested at 1 ppm, come to fine out that my Nitrates are 40ppm.

I am adding more fish next week. Currently I have 50 cats at about 1lb each and about 20 goldfish (big).

Florida Fish Farms says I have to buy $35.00 minimum order. I was going to add 50 cats and 50 brim.

Is that to much for 1000 gallons? ( about 6 gallons each) or I can larger cats only.

Do cats eats their young.

Opinion  please!

Happy Holidays!!!

[TCLynx]

Uh, what is your filtration.

If you have 1 ppm of nitrites, I would say no you should not add more fish.  You are either not cycled up yet completely or you don't have enough filtration for the load you do have or you are feeding them too much.

The fish tank is not the primary concern for fish stocking.  I would say a total of 100-150 fish is ok in a 1000 gallon fish tank but only if you have enough filtration for them.  Do you have a total of 150 cubic feet of media bed?  If you do then you could probably have that many fish total in the system but I would wait till both your ammonia and nitrite drop to 0 ppm with the original fish before adding any more and only get more if you have enough filtration for them.

Easy rule of thumb for fish you intend to grow out to only 1 lb each, is one fish per cubic foot of media bed or one fish per 3 square feet of 1' deep raft bed.  You can always go with less fish, if you stock more than that you are pushing things and could have lots of fish die due to lack of bio-filtration.

With channel catfish since they grow big, I generally like to stock less of them since a 3 lb fish is very likely in a season down here in FL.

I don't know about channel cats eating their young, it is highly unlikely you will be breeding any of them as they are not even mature enough for breeding till they are 3-5 years old.  Now Bigger fish may eat smaller fish, though catfish are relatively lazy if being fed well so are not likely to eat the small fish unless the small fish are very slow and sluggish.  That said, there are always less fish harvested from a pond than are stocked and I'm sure some are eaten.  My channel catfish were always too well fed to eat the escaped tilapia unless it got too cold for the small tilapia.

I've always kept new small fingerlings separate from my bigger fish so I don't know if your current fish would eat your new fingerlings.  I often use floating cages to keep the smaller fingerlings separate from the bigger fish if I can't keep them in a separate tank/system.

[Dan Ponton]

 The 1ppm is from a test strip, but normally with the liquid test it is always zero. The 40 ppm nitrates is from the test strip also. I have about 190-200 CF of grow beds and DWC.

I have the system cycled and cat fish since April 2012. The plants are growing but my ground based plants grow as good or better that my Aquaponics plants except my Tomatoes which are out of control.

I will keep the fingerlings in a floating tub for awhile.

The gold fish were feeders and the cats did not eat them so they may not eat the fingerlings.

[TCLynx]

Ok, run the regular dropper test to make sure your ammonia and nitrite are indeed 0.

If your nitrates are 40 ppm, you have plenty of fish to feed the plants you have, you might want to try a dose or seaweed extract and/or chelated iron since deficiencies will definitely slow the plants down in a newer system.  If your pH is high you may need to add chelated iron regularly since the plants will have trouble taking up iron when the pH is high.  What is your system pH?

You said you have 190-200 CF of grow beds and DWC???  How much is media bed and how much is DWC?  See media beds 1 cubic foot per fish is a good level and DWC it is more like 3 square feet of raft per fish to be able to have enough filtration.

But as I said, if you have 40 ppm of nitrates, you have enough fish to support the amount of plants you have growing so some other deficiency could be your limiting factor.  I find spraying with some seaweed extract can help even more than dumping it into the water.  One ounce of extract to 1 gallon of water and spray the plants (Be sure to do it when the spray can dry before the plants will get scorched by hot sun.)  Heck, Molasses can be used the same way to spray on the plants too.

With the powdered Iron Chelate I use, I'll often put a tablespoon full into each 100 gallon media grow bed under the water inlet every two or three weeks or whenever I see signs of Iron deficiency.

I wouldn't say the slow growth is due to not enough fish unless you have 0 nitrates and the plants are showing signs of nitrogen deficiency.  I've run systems with great plant growth with the nitrate levels only about 5 ppm.

The quality of the fish feed can also have a huge effect on plant growth and productivity.  If it isn't a complete feed, you may really be seeing some deficiency issues for the plants and I would definitely recommend some seaweed extract for the plants in that case.

[Dan Ponton]

I reason I am interested is that I have read on other post sites that people are running nitrates up into the high hundreds as long as the ammonia and nitrites are at zero.

I wanted some insight from other Floridians. I understand that the lethality of ammonia increases with temperature. The hotter it is, the greater chance of fish kills.

Thanks

[TCLynx]

While you can run with elevated nitrate levels, I don't believe there is much benefit to the plants to have the nitrates up too extremely high especially if there are other limiting lacking nutrients that are not allowing the plants to utilize the nitrates as effectively.

If you have a system with elevated nitrate levels and some anaerobic areas (build up of sludge) you may also wind up seeing denitrification or the conversion of nitrate into nitrite to be off gassed.  If there isn't a good amount of degassing after where ever such denitrification is happening, you could be sending nitrite and other dissolved gasses back to your fish which could be really unhealthy for them (hydrogen sulfide and other things.)

Now here in FL where we get good weather for fish to eat lots of food through summer but not as many plants that grow well in the heat, I've experienced really high nutrient levels in a system through summer and then they get used up well in the winter when lots of greens grow well using up nutrients but the fish don't eat as much because the water cools off and the nutrient levels drop to 0.

I find that here in FL, (at least on my source water) one major limiting factor is pH being too high and locking out certain nutrients like Iron.

[Dan Ponton]

I bought a nitrate test kit yesterday. Nitrates are at 10ppm while ammonia and nitrites are 0ppm. Phosphates are almost off the scale.

Have you ever heard of using banana leaves for PH down control. it is very popular in the aquarium community. And it is good for the fish and shrimp they say.

TCLynx said:

While you can run with elevated nitrate levels, I don't believe there is much benefit to the plants to have the nitrates up too extremely high especially if there are other limiting lacking nutrients that are not allowing the plants to utilize the nitrates as effectively.

If you have a system with elevated nitrate levels and some anaerobic areas (build up of sludge) you may also wind up seeing denitrification or the conversion of nitrate into nitrite to be off gassed.  If there isn't a good amount of degassing after where ever such denitrification is happening, you could be sending nitrite and other dissolved gasses back to your fish which could be really unhealthy for them (hydrogen sulfide and other things.)

Now here in FL where we get good weather for fish to eat lots of food through summer but not as many plants that grow well in the heat, I've experienced really high nutrient levels in a system through summer and then they get used up well in the winter when lots of greens grow well using up nutrients but the fish don't eat as much because the water cools off and the nutrient levels drop to 0.

I find that here in FL, (at least on my source water) one major limiting factor is pH being too high and locking out certain nutrients like Iron.

[TCLynx]

I'd never heard of banana leaves for pH down.  How would you go about it?

[Dan Ponton]

I have been reading a little about it but not sure. I would think you can but them in a mesh bag and something to keep it down, and just put it in with your fish. I am soaking some dried leaves from my banana plants in 2 gallons of well water to see if it works.

They release tannin like peat moss does. I am also looking into peat moss to see if it works. I can put up with black water if my PH will drop.

Has not rained much here so I don't have any in my barrels.

TCLynx said:

I'd never heard of banana leaves for pH down.  How would you go about it?

[TCLynx]

Yea, I know how it is to need rain water and not have any in storage.  I'm along the Florida Ridge and we seem to miss out on much of the rain that seems to fall on the rest of Florida.

I've tried the logs in a tank, I use lots of peat for my seed starting so my towers have peat in them and it is still rarely enough to have much effect on my well water when I have to use too much of it.  I may have to give in and get an RO filter.