Fry/Nitrate levels?

[Cathy G]

I jumped in over my head and pulled my Bolivian ram's eggs. Well, I have around 175 1/2 inch fry now, and they are all in my 30g. So, nitrates are becoming a problem... what are the best/worst parameters? I have been doing daily 20% w/cs but my levels are now 20. Yesterday and today I did 50-60% w/cs. Is 20 too high for the fry?

I don't have any other big tanks... I think I have probably been over feeding, this has come to a screeching halt. I also added lots of hornwort and a tank light for it. It is barebottom, has one external power filter and 2 sponge filters. Oh, I am squeezing/cleaning the sponges daily...

Any advice? (I can't possibly do the culling thing...)

Cathy

 

[tjudy]

Stick with the 50% water changes daily. If possible, spread the feedings out so that you can feed less each time. It is important that all the food be eaten and digested. Over feeding at one time will usually end up with some uneaten food and some food that will pass through a fry's gut without being completely digested. All that really means is that you are not getting efficient return on the food... some of it is becoming nitrate without helping grow the fish.

 

[orcus332]

Over feeding at one time will usually end up with some uneaten food and some food that will pass through a fry's gut without being completely digested. All that really means is that you are not getting efficient return on the food... some of it is becoming nitrate without helping grow the fish.

Ted, I'm not sure why a large meal for a fish would result in incomplete digestion of the feed. In other words, why are feed intake and feed efficiency negatively correlated? Thanks!

Cathy,
I don't think that squeezing/cleaning your sponges daily is a good idea. Since you don't have a substrate, the majority of your microbes will be in the filter sponge. By removing the microbes from the sponges, you are decreasing the potential of your biological filtration. I think that daily water changes are your best defense against high nitrates.
What is the nitrate level of the water your are adding to your tank?

 

[lab]

Ted, I'm not sure why a large meal for a fish would result in incomplete digestion of the feed. In other words, why are feed intake and feed efficiency negatively correlated? Thanks!

That is not what Ted wrote. Only that if feeding more than a given amount some food will not be digested. That is not the same as negative correlation.

If you feed a lot, you can actually see the food being passed without any digestion. I've seen it with blood worms

Lars

 

[Cathy G]

Hi Orcus,

I am using mostly RO, with a little of tap water. (A usual mix is 7-9g RO to 2-3 tap. To this mix I add Kent's RO right for soft water.) The water out of our tap is VERY hard with pH of 7.6 - 7.8.

I put purigen in the filter box now, and am only feeding the fish 3-4 times a day as opposed to every 3 hours! I'll cool it on the sponges, maybe only squeeze/cleaning them a couple times a week - they are awful dirt magnets, but I know that nitrates are sure better then nitrites and ammonia...

Yesterday I did that other 50% change and this morning the nitrates are down to 5-10. Much better! I added some trace and excell to jump start the hornwort - hopefully it will use up a bunch of the nitrates as it gets growing.

I have a birthday coming up - maybe I'll ask for a 40g breeder tank?!

Cathy