[AnionAndCation]

Recently lost 2 PRLs and an oto due to some unknown reasons...
My first reaction was to check water parameters, and they were:
pH - 6.4
Ammonia - 0
Nitrite - 0
Nitrate - 0
GH - 7
Temperature is set at 72 Fahrenheit
Substrate is Fluval planted stratum
Very few water changes, daily top off with RO/distilled water from Walgreens

GH may be high, but I've had that GH for a couple of months now, didn't have casualties until recently

Tank has a Fluval 206 and a sponge filter, inside the Fluval 206 I have Purigen, Matrix and BioMax as medium, I'm using a Finnex FugeRay Planted+ on the tank

The tank only has PRLs and otos in it, plus a bunch of java moss and an echinodorus. I have never seen any common aquarium pests in my tank, be it scuds, planaria or hydra or anything else, tank water is crystal clean and highly oxygenated with that sponge filter running 24/7, I'm not dosing any kind of fertilizer/plant supplement

Shrimps are fed on a rotational schedule with Hikari shrimp cuisine, Hikari algae wafers, BorneoWild grow and Mosura BioPlus (all grinded into powder), I feed once a day including occasional starve days, tank has a small amount of hair algae, green spot algae and minuscule amounts of brown algae

Can't seem to figure out why the shrimps and otocinclus died!

 

[AnionAndCation]

How old were the shrimp?

The shrimps are all sub-adult to young adult, I got them as peewees

 

[AnionAndCation]

Nothing really jumps out at me. Not familiar with purigen enough to know if it can cause probs.
How long has the tank been running?
Seems like maybe your feeding sched. (once a day) is more frequent than people use ? But considering your parameters, apparently not an issue.

That's the problem, I can't see an issue...

 

[AnionAndCation]

Sometimes deaths are random. If you don't see an issue (and I don't), perhaps they were just meant as "feeders" in the real world and not meant to survive long. (What I mean by that is that some shrimp are just not destined to survive long when born.)

Have you had any other incidents since those?

I have not had any incidents since those, but who knows... Really don't want to lose any more shrimps. Or perhaps I should start keeping neos

But then there must be a reason for everything...

 

[AnionAndCation]

+1

I have had some shrimp like that, they also never seem to grow to full size either.

That's the problem I'm having, there was a month where the shrimps just kept molting and growing, I could see them getting bigger and bigger, getting closer to breeding age and then suddenly they start dying

 

[AnionAndCation]

If your too died too, there is something going on. My otos never die, as I have put some through some bad conditions and they come out fine. Give the full spectrum size of the tank last water change tds. How old is the tank.

Also feeding daily seems much, I feed every other or every 3rd in highly populated tanks. Plus you are feeding pretty high protein foods. They could be growing to fast to molt. I would take out the hikari and do organic blanched spinach in its place.

The tank is a 15 gallon column tank, around 12x12x18, I don't have a tds meter but I've been using purified water from Walgreens, tank has been running for around 4 months

Maybe feeding was one part of it, I haven't paid attention to protein content before

 

[AnionAndCation]

Feed less for sure and use blanch spinach for a good calcium source to help them molt properly. The over feeding could be it. Feeding to much will create all kinds of issues. Especially in such a small base area foot print.

What substrate do you use. You need to get a tds pen, very important part of keeping high end shrimp

Are you using a test strip or a water based kit to get readings?

I'm using API's liquid based test kit

It sounds like overfeeding was the problem, I will change all of the above, as for TDS pen, I thought of it as sort of an optional thing, never really considered getting it, what would be advantages of having a TDS pen?

 

[AnionAndCation]

Tds pen tells you when water changes are needed when the tds is to high and big swings in tds or to high of tds can cause stress and deaths

I see, thanks