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managing shrimp & duckweed

hwscot

Member
Joined
15 Nov 2021
Messages
80
Location
Montrose
Hi, still relatively new to shrimp. Please bear with the backstory so I can explain the question:

I started by adding some neocaridina to a small tank (25L PAH) which, with a marina box on the back for the female, I have used for a while for livebearer newborns. I've moved them on to a grow-out tank after a couple of weeks. I now realise I've not been moving them on soon enough, since a couple of weeks with the tank empty of young livebearers has seen a massive increase in shrimplet survival. The tank has a sponge filter, I keep TDS around 200 - 250, but this isn't a question about parameters or filtration; it's about managing the routine maintenance.

Surface has duckweed, red-root floater and occasional trimmings from other tanks. It gives a nice level of shade / light diffusion, fry and shrimplets like to hang out in the roots. The odd bit of wood, banana leaf. Sand / gravel substrate a bit gungy, full of snails. I cull the snails and lift the worst of the mulm with a dip tube every now and then as a kind of late night zen thing.

Given how well the shrimp are doing, I'll either stop using it for livebearer newborns, or shift them on to the growout quicker. (I keep the two stage thing for young fry, with a first cull / selection before moving them into the larger growout - that means leaving them in the first tank long enough to make a judgment on colour etc.)

Problem is cleaning & water changes. The floating stuff makes it hard to do that without picking up the odd shrimplet. If I want to thin out the duckweed / rrf, same problem. I'm wary of using the dip tube because it's so hard to make out young shrimplets, who seem most attracted to the gungiest substrate. I'm reduced to clumsy guddling between small jugs of mixed duckweed, substrate and snails, plus a couple of shrimplets, trying to decant rubbish without losing shrimplets.

Any ideas on managing this? Ditch the duckweed (will take forever!) and go for a chunkier floater (Limnobium?) .. rely on the shrimplets to get themselves out of the way if I'm simply thinning out duckweed? .. accept the odd shrimplet loss? Refine my method for decanting shrimplets from changed water / skimmed duckweed? I'm reluctant to lose the duckweed as it works so well in every respect apart from physical management. In any case, how do people do even minimal water changes in tanks with shrimplets without catching them in the process? Any specific version of the various syphon / gravel cleaner / water changer thingies particularly good for small tanks? Dennerle nano?

Couple of pics of the tank. Going for a bit of an Alexander Williamson vibe.
DSCF2720 Xn_AIS 2k.jpg
DSCF2716 Xn_AIS 2k.jpg
 
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castle

Member
Joined
19 Dec 2015
Messages
937
Location
UK
I’d suggest you take all the duck weed out, put it into a large clear container with tank water. Add a sinking shrimp food to the bottom, give it a couple of hours, if no shrimp there discard the lot, else if there are shrimp remove duckweed and save those lil shrimplets.

In reality, I take all surface plants and whatever comes with them and give them to the pond. 😬
 

Witcher

Member
Joined
15 Jan 2020
Messages
308
Location
London
@hwscot what about putting something like this on the water change hose inlet? It will still attract lots of gunk etc while your shrimplets will be safe. Been there, done that.
 

Wookii

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Joined
13 Nov 2019
Messages
3,417
Location
Nottingham
In a low tech shrimp tank, I'm assuming your water change is only about 10% a week? For my 20 litre shrimp tank I use a drip acclimation kit to drain the water out into a large jug:


It has a sponge over the intake end so only water can get through. Being a shrimp tank there should be no real need to vacuum the substrate.

For the duckweed removal Darrels (@dw1305) probably now patented "Duckweed Duster Buster" technique is probably the easiest. Put your arm (possibly just your hand given the tank size) under the water, and draw it out slowly. The shrimp should all move out of the way leaving you with a duckweed covered hand to rinse under the tap, and quite literally "rinse and repeat" as necessary.
 
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hwscot

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Thread starter
Joined
15 Nov 2021
Messages
80
Location
Montrose
I’d suggest you take all the duck weed out, put it into a large clear container with tank water. Add a sinking shrimp food to the bottom, give it a couple of hours, if no shrimp there discard the lot, else if there are shrimp remove duckweed and save those lil shrimplets.
this falls into the 'doh, why didn't I think of that' category. Thanks!

what about putting something like this on the water change hose inlet? It will still attract lots of gunk etc while your shrimplets will be safe. Been there, done that.
Witcher .. can't get that to open - site seems down thought will try again later. From the url itself looks like it's some sort of sponge (presumably coarse) .. maybe like you would put over the intake for a canister filter? Do you have another link to something similar, or maybe just a description?

We used to have a garden pond: sadly had to come out due to repeated vandalism. The hankering remains.

Thanks, guys, both these look like ways to reduce the guddle factor;
 

hwscot

Member
Thread starter
Joined
15 Nov 2021
Messages
80
Location
Montrose
In a low tech shrimp tank, I assuming your water change is only about 10% a week? For my 20 litre shrimp tank I use a drip acclimation kit to drain the water out into a large jug:
if that. Though I feel my existing rough and ready drip kit would be offended if I went for a younger, sleeker model.
It has a sponge over the intake end so only water can get through. Being a shrimp tank there should be no real need to vacuum the substrate.
if I keep it shrimp only, substrate should be much cleaner, right enough, and snail population shrink

For the duckweed removal Darrels (@dw1305) probably now patented "Duckweed Duster Buster" technique is probably the easiest. Put your arm (possibly just your hand given the tank size) under the water, and draw it out slowly. The shrimp should all move out of the way leaving you with a duckweed covered hand to rinse under the tap, and quite literally "rinse and repeat" as necessary.
Given this more or less happens anyway ..! :)
 

dw1305

Expert
UKAPS Team
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7 Apr 2008
Messages
14,253
Location
nr Bath
Hi all,
I’d suggest you take all the duck weed out, put it into a large clear container with tank water. Add a sinking shrimp food to the bottom, give it a couple of hours, if no shrimp there discard the lot, else if there are shrimp remove duckweed and save those lil shrimplets.
Sensible. I <"use a white tray"> (below, like you get in a butchers etc.) or white washing up bowl etc. and the essential <"pound shop" tea strainer">.

blackworm_tray-jpg.106146

It has a sponge over the intake end so only water can get through
Even more sensible.
probably now patented <"Duckweed Duster Buster"> technique is probably the easiest. Put your arm (possibly just your hand given the tank size) under the water, and draw it out slowly. The shrimp should all move out of the way leaving you with a duckweed covered hand to rinse under the tap, and quite literally "rinse and repeat" as necessary.
Alas, negotiations with Rob Delaney and / or ADA have broken down. It may have to be <"Dragon's Den"> and I'll need some-one else to come in for <"aesthetic reasons">.
Thank you, I was going to do one of the kit in the analytical lab. but I'll have to get some-one else to front them, because I look like a gargoyle and sound like a cockney market trader.

cheers Darrel
 
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