Netting (quick) fish in established (planted) systems

[jjohnwm]

Sometimes there’s not a choice you need to take some stuff out to net a problem fish. The plants will be fine lowering the water. To answer your question draining the water out and keeping it to refill the tank back up is totally fine. In fact with invertebrates your better off not doing a major water change or you run the risk of stressing out the shrimp and causing them to all molt also any berried shrimp will loose their clutches. It is definitely in no way equivalent to reusing motor oil.

I'm not a shrimp "E-guru", but I had a colony go from a dozen or so to many thousands spread over a number of tanks, and removed/sold/traded hundreds as well as using many more as feeders. They thrived despite the Neanderthal-style care they received, which was the same as all my fish. It involved draining down all the tanks to within an inch or two of the bottom, with fish often laying on their sides, and then filling up with brand-new, untreated well water.

Delicate invertebrates are always thought to fare poorly with large water changes. I'm sure that might be true if the changes are few and far between; the water in any tank degrades over time, and then suddenly changing most of it exposes the critters to big abrupt shifts in parameters. But frequent massive changes don't do that; weekly, or even more frequent, changes mean that the water is replaced before it has significantly altered in chemistry, so the animals are living in stable parameters rather than wildly swinging ones.

Don't change the water when it gets old; change it before it has a chance to do so.

I'll stand by my viewpoint that if you are going to the trouble of removing 90% of your water...as long as you do it regularly and often...the best use of that time and effort is to change it at the same time. I might think differently if my water was treated and reverse-osmosed and then re-mineralized and artificially buffered and pH shifted and who-knows-what-else...but we don't it that way in the caves.

 

[Deadeye]

Haven’t used it personally, but I’ve seen these used for catching reef fish. This one’s a bit pricey, but you can probably get similar products cheaper (or diy it):

https://www.amazon.com/NYOS-Floating-Fish-Trap/dp/B09FKM6XMG/ref=asc_df_B09FKM6XMG?mcid=ab89735abe6c3cb4b69d64374212d706&hvocijid=504862787142322595-B09FKM6XMG-&hvexpln=73&tag=hyprod-20&linkCode=df0&hvadid=721245378154&hvpos=&hvnetw=g&hvrand=504862787142322595&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1022074&hvtargid=pla-2281435179978&psc=1

Having destroyed many scapes trying to catch fish (as all of us have), a trap is probably the best way to go.

 

[TheWolfman]

I'm not a shrimp "E-guru", but I had a colony go from a dozen or so to many thousands spread over a number of tanks, and removed/sold/traded hundreds as well as using many more as feeders. They thrived despite the Neanderthal-style care they received, which was the same as all my fish. It involved draining down all the tanks to within an inch or two of the bottom, with fish often laying on their sides, and then filling up with brand-new, untreated well water.

Delicate invertebrates are always thought to fare poorly with large water changes. I'm sure that might be true if the changes are few and far between; the water in any tank degrades over time, and then suddenly changing most of it exposes the critters to big abrupt shifts in parameters. But frequent massive changes don't do that; weekly, or even more frequent, changes mean that the water is replaced before it has significantly altered in chemistry, so the animals are living in stable parameters rather than wildly swinging ones.

Don't change the water when it gets old; change it before it has a chance to do so.

I'll stand by my viewpoint that if you are going to the trouble of removing 90% of your water...as long as you do it regularly and often...the best use of that time and effort is to change it at the same time. I might think differently if my water was treated and reverse-osmosed and then re-mineralized and artificially buffered and pH shifted and who-knows-what-else...but we don't it that way in the caves.

Shrimp just don’t require massive water changes. Dilution is the solution. They’re not monster fish. You’re entitled to your opinions and I have mine. I’m not gonna argue with you from your podium with your dramatic pauses.

 

[Conchonius]

Shrimp just don’t require massive water changes. Dilution is the solution. They’re not monster fish. You’re entitled to your opinions and I have mine. I’m not gonna argue with you from your podium with your dramatic pauses.

Entirely true. However, they don't hate them either. They will tolerate large water changes quite readily, so if you keep other fish with them or just prefer large water changes, there's nothing stopping you.

As for the dilemma in this thread, I personally would leave the lemons be. As long as the tank has plant cover, enough shrimplets will escape that you will soon have a saturated population. Unless you have some of these line-bred, SSSR+ grade, diamond-rank, black-rarity, six-star specimens that go for $50 apiece, there's no harm in letting a few become snacks for the enterprising tetra. Once they start breeding, you'll soon have way too many of the buggers already.

Many shrimp-people, I feel, fret too much over too little and treat shrimp as fragile, beautiful butterflies that will keel over the moment you look at them funny instead of what they really are: water cockroaches that would merrily breed in a toilet bowl if given a chance. If they call them "skrimps", for example, you can write them off as a lost cause.

A wait-and-see approach I think is the best option here, if too many of the first few batches get eaten then some countermeasures might be in order.

 

[Andyroo]

Thanks all, this is useful.

Part of my issue is cost & replacement-access: there's one seller/breeder on this island & currently he's more recreational. As such, I bought 6 as I wasn't up to further financial risk in a first-try. To this I'm pretty patient, so, as much as I'd prefer a faster turnaround, I am willing to wait through X% baby-mortality to mitigate parent mortality risks via drain, rummage, fill etc. I have a knack for squishing things and/or not seeing them lodged in the decor.

The breed-quality's ... kind'a naff. Of the original 6 there are 3x actually a reasonable blue & 3x burnt purple-ish, seeming to get duller as they grow. I'll do a lot of higher-risk activities & culling once this ball starts rolling, and i expect the loaches will appreciate the abundant browns.

Meanwhile I'd love to have been breeding the lemons, but it seems the oscracods are gobbling-up any eggs before I see them. Another reason to relocate the fish... eventually.

Thanks again,