Random spate of shrimp deaths

fishbro

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21 May 2018
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hey folks, I seem to be having a lot of amano shrimps dying lately and it’s really stumping me as to what is happening. Every few days I’m finding one of my amanos all pink and dead on the bottom of the tank. Today I found one scooting around the bottom pretty much upside down. It seemed to be flinching as if it was trying to moult but wasn’t getting anywhere and after a while it just seemed to die. I have noticed a reduction in shrimp shells (is that the term?) lately as before I was usually finding one every other day (around 30 ish small-medium amanos in the tank).

This seems to be coinciding with crypt melt too and I am equally confused as to what has caused that. I had a bad wave of crypt melt a few months ago when I switched from gravel to tropica soil for the substrate, so naturally the massive change in chemistry caused that, but everything appeared to have recovered fine until now. Nothing major has changed in the past few weeks, just been keeping up with the maintenance. The only thing I have done is add some Monte Carlo to try and get a nice carpet going, though my garras love to dig it up!!

I need to pick up a fresh test kit on Monday as mine is out of the reagents, but I am doing 50% water changes weekly with a filter clean every other week (it’s rarely very dirty). I can only wonder if something with the local water supply has changed recently?

Is there anything in particular that would cause shrimps to fail to moult (then die)? I’m a bit sad about it because I’ve really warmed to having these little critters, they add a splash of personality to the tank while also helping with algae!

Cheers :)
 

fishbro

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21 May 2018
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How big is the tank and what are you feeding the shrimp and plants?
It’s 200L (plus 15L for the filter). For the plants I use TNC complete at 21ml a day and the shrimp get fed an algae wafer or some hikari shrimp pellets every now and then. Generally there’s plenty of bits of algae and scraps for them to eat (I’ve seen them fend off fish to keep hold of food lol).

Noticed 2 empty shrimp shells today so that’s a good sign, maybe I just got unlucky?
 

alto

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24 Dec 2014
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While it’s possible that something has come in with recent water changes - look about your area for recent roadworks or construction, contact your water supplier to see if they’ve added/switched sources (depending on area, it’s not uncommon for water supplier to draw from more than one water system) - also consider calcium/magnesium levels in your tank (again your water supplier should have stats on these)

There are specialized shrimp mineral foods available (not cheap but presumably designed to be palatable enough for sufficient mineral uptake)
 

fishbro

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21 May 2018
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While it’s possible that something has come in with recent water changes - look about your area for recent roadworks or construction, contact your water supplier to see if they’ve added/switched sources (depending on area, it’s not uncommon for water supplier to draw from more than one water system) - also consider calcium/magnesium levels in your tank (again your water supplier should have stats on these)

There are specialized shrimp mineral foods available (not cheap but presumably designed to be palatable enough for sufficient mineral uptake)
Hmm I think any special food I add would be gobbled up by the mollies pretty sharpish! You may have a point about roadworks, there are some houses being built at the other end of the village. I'll see if I can find out more.

Perhaps your shrimp population is levelling off due to available food/energy.
Could be... I wonder if some of them were just reaching their lifespans? I'm waiting of a delivery of lots more plants so once the tank is finally heavily planted I will likely add another load of shrimp. I'm wondering if they didn't have enough space to hide.
 

alto

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around 30 ish small-medium amanos in the tan
Unless these are all males, I’d be surprised if they’re very old - Amano shrimp seem relatively long lived, there are lots of reports of 3-5 yr old Amano

If you place the food in areas only accessible to shrimp - Molly size should make that fairly easy :D

Is it possible the Mollies are harassing shrimp enough to cause damage and shrimp are dying?
 

Simon Cole

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25 Dec 2018
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I would say that my Amano is about 5 years old and huge.
I was not going to say this, but every time I have tried to force them to eat algae, they turned to plants. I discussed this with Rachael O'Leary and she said that her Amanos in 30 years of experience never ate plants.
With Amanos, I was never able to keep more than one or two - and I suspected at the time that the mature ones became very territorial. I didn't want to mention this either, because many people keep large numbers of them. But my experience is that the population usually crashed out pretty quickly if additional food is not provided. I generally feed my amanos one pellet each per day or they will damage my plants. I know that is controversial, but there you go. It is what I do, and it keeps them all alive. They are very big shrimp and need plenty to eat.
 

sparkyweasel

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I read somewhere, but can't remember where, or find any notes (grr), that there are a number of very similar-looking species with different habits. So what appear to be Amano shrimps, and were sold as such, may be something else.
It would explain people's varying experiences with 'Amano' shrimps. You're not the only one to find their 'Amanos' don't eat algae.
 

alto

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Close examination generally reveals some visible differences between “true” Amano and the “Japonica ‘var’ “ which are (recently) more commonly seen on Farm Lists

A local shop has been receiving a “Japonica ‘var’ “ which gets rave reviews (best hair algae eaters ever) - they are a similar appearing shrimp but decidedly more aggressive than Amano (males appear to get larger, shipments seem to be female dominated)
 

rebel

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Could be an ammonia spike (maybe increased chlorination in the water?) given the Crypt melt also.

btw filter clean every other week is not required. Hopefully you are not cleaning the media too throughly.
 

fishbro

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UK
Interesting! I didn't know about "fake" amanos, will have to watch out for them.

Could be an ammonia spike (maybe increased chlorination in the water?) given the Crypt melt also.

btw filter clean every other week is not required. Hopefully you are not cleaning the media too throughly.
Generally I only clean once every 1-2 months, but with the crypt melt the filter is getting clogged fast even though I am taking the dead leaves out as often as I can. About half of the plants in my tank are (...were) crypts, so as you can imagine it's quite a scene of destruction lol. I generally just give the media a little rinse in tank water and that's about it. The pre filter gets a thorough cleaning, but the rest is generally left alone
 
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