Petshrimp.com Discussion Forum

Hi guys,

Just wanted to announce and share a discovery that I have made over some time.

I have advocating the use of tree leaves, beech and oak in particular, over quite some time. People in Europe who have been keeping shrimp for a long time also use oak and beech leaves in their tanks quite frequently.

However, after hearing some reports from Germany that some shrimp species *mysteriously* stopped reproducing until the same individuals were put in a different tank and experiencing the same problem myself in my tanks with oak leaves in them, I decided to do an experiment.

I took out all oak leaves out of some tanks to compare the shrimp in there with the shrimp that still had oak leaves in the tanks. Surprisingly, the shrimp without the oak leaves started reproducing again! Also, the hair algae that was growing in those tanks *on* the oak leaves disappeared!

Also, I had been noticing that the shrimp populations that *were* reproducing in the tanks with the oak leaves were having trouble gaining numbers. Many young would die a couple of days after hatching and the young that survived would die right when they reached adulthood. The shrimp population was keeping stable but was not growing (another reason why I have not offered new species for sale yet...).

So...now I have taken out all oak leaves and things are back to normal. The shrimp are eating voraciously and most females are carrying eggs again. I am suspecting that the bioload in those tanks was just too large when the oak leaves started decomposing, or there were some chemicals in the oak leaves, besides tannic and humic acids which are exhausted after a week or two, that affected the shrimp adversely. This seemed to be more the case with leaves that had just freshly fallen off of the tree than with leaves that had been on the ground outside for months before beeing collected.

So...now I am back to the basics. I have s plain sand substrate with a sponge filter and that's it. I feed fish food and nothing else (either pellets or flakes). I still think plants are fine, especially for nutrietnt export and additional "filtration", but the oak leaves have definitely gone out the window.

I will have to change my articlels accordingly to reflect this discovery (I updated my articles generally from time to time anyway so it's always good to check them periodically). This is what I love about this hobby. You can never sit down and say: "Now I know it all and there is nothing more to learn." There is ALWAYS more to learn, discover and more methods to pefect. That's what keeps things exciting.

Mustafa

Mustafa wrote: This seemed to be more the case with leaves that had just freshly fallen off of the tree than with leaves that had been on the ground outside for months before beeing collected.

Perhaps the oaks have developed a natural pesticide that affects shrimp. Do you know what species of oak you are using?

Possibly, although the copepods I have in the same tanks did not seem to have been affected by this so it's strange the shrimp did. I have no idea what species of oak I used. I used at least two or three different species...I could tell by the size and shape of the oak leaves. One species actually still had reddish leaves eve after the leaves had fallen to the ground.

My shrimp are doing great again since I have removed the oaks. I mean...it was never really necessary to have the oaks as long as you fed your shrimp enough and had algea in your tanks, but it was a nice additional supply of food. Too bad it has these side-effects.

The dangerous thing about these side-effects is that they are hardly noticable. Your shrimp act and do just fine until the day they day. More and more shrimp disappear, discard their eggs or the hatched shrimp just disappear after a day or two. If you do not watch closely you won't notice these effects and your shrimp population will probably decrease *very slowly* over time. It's a creeping problem.

Mustafa

Couple of possibilities here with the leaves.
First I noticed your in NYC. I escaped from there 25 years ago.
If these are locally collected leaves they are going to be loaded with heavy metals from the pollution. Shrimp are sensitive to them. Even roadside leaves along the thruway would have enough junk to cause problems. Up here in farm country we are actually warned away from allowing our animals to graze to close to the road because of this. It's going to be so much more concentrated where you are.

Oak leaves contain lots of tanins. They are very acid when they decompose. Also large amounts of leaves and stuff will actually rob nitrogen from a land garden for a while until the decomposition is further along. I wouldn't think this would be a big problem unless your putting in lots of leaf litter. I don't really know......upsetting the nitrogen cycle a bit in a small system does cause problems.

My bet is on the pollutants the sidewalk trees absorb. One of the reasons they are planted in the first place.

SueNH wrote: If these are locally collected leaves they are going to be loaded with heavy metals from the pollution. Shrimp are sensitive to them.

I would have expected the copepods to be affected too.

Also large amounts of leaves and stuff will actually rob nitrogen from a land garden for a while until the decomposition is further along. I wouldn't think this would be a big problem unless your putting in lots of leaf litter. I don't really know......upsetting the nitrogen cycle a bit in a small system does cause problems.

More likely, the problem would be a drop in oxygen levels.

The tannins actually leached out after several days completely and, as Brad already indicated, the copepods did not get affected so it's strange that the shrimp would. I do have a feeling though that it does have something to do with the decomposition of the leaves in such a small system and the resulting bio load.

By the way...I am trying to escape from NYC, too. Give it 2-3 years and I should be in sunny southern california.

Mustafa

Mustafa wrote: Give it 2-3 years and I should be in sunny southern california.

With some nice shrimp ponds, I hope.

Bradimus wrote:With some nice shrimp ponds, I hope.

You can *bet* on that. I would have those ponds already (inside a greenhouse of course) if it had not been for the fact that it's kind of hard to dig ponds in Manhattan. All this concrete makes this undertaking quite difficult.

Mustafa

mustafa,

it sounds like you advocate using a non-planted tank as opposed to a planted tank to raise shrimp. am i correct in this assumption? it seems contrary to what others recommend. do u think this method works better than keeping shrimp in a planted tank?

-r

The shrimp don't care either way. They are fine with or without plants. There are pros and cons to having plants. Plants can help in "filtrating" the water by exporting nutrients from it (when you prune the plants you take those nutrients out of the system). On the other plants can compete with the type of algae the shrimp like to eat.

I personally don't use many plants at all for practical reasons. I am constantly catching and moving around shrimp from tank to tank or sell surplus shrimp ot to other people. It would be impracticle for me to have to hunt my shrimp among the plants, which would give them excellent hiding opportunities.

In my 55 gallon tank I do use a floating plant very extensively (Limnobium laevigatum) that helps me tremendously with nutrient export.

Mustafa

Mustafa,

Have you noticed any change in the growth rate of your shrimp since removing the leaves?

Bradimus wrote:Mustafa,

Have you noticed any change in the growth rate of your shrimp since removing the leaves?

Hey Brad!

Oh yes! I have noticed a huge change in all respects. Not only are my hatchlings not dying anymore (which they were before) but they are growing and doing well. I feed them more often now also, so they are growing pretty quickly. I had some problems with my adults dying mysteriously, too. That problem is gone and death rate is 0. My hypothesis that the leaves were responsible for the problems in my shrimp tank turned out to be true.

So...all my problems are gone. My shrimp are happy and doing great once again. Removing the large piece of driftwood from my 55 gallon tank had the same positive effect as removing the leaves. I guess "less is jsut more."

Mustafa

Mustafa wrote: My shrimp are happy and doing great once again. Removing the large piece of driftwood from my 55 gallon tank had the same positive effect as removing the leaves. I guess "less is jsut more."

Mustafa

hmm.... i have two pieces of driftwood in my tank. is it your recommendation that i take them out? i have a big momma shrimp carrying berries in there and she seems to be doing fine. the larvae will be housed in a separate grow out tank. do u think the use of driftwood affects fertility?

If the driftwood has not affected your shrimp, there is no reason go take it out. Just observe your shrimp and judge from that. If they are not picking at things and just sitting around, lose appetite etc. then you can try removing the driftwood...otherwise leave it. "If it aint broke, don't fix it."

Mustafa