Over a dozen dead larvae; new heater to blame?

[shrimpy4]

My shrimp have been breading like crazy heading into the winter. There’s consistently been at least a half dozen larvae and multiple berried shrimp at any day for the past couple of month.

My tank was getting down to 60 degrees due to the winter, so I purchased a 50W heater about 5 days ago. Keep it fully submerged, temp stays at 66 degrees or so in the tank. the first day or two the shrimp seemed a bit agitated and the larvae hovered near it. I figured they liked the warmth.

Haven’t seen much movement, lately taking a closer look just now I’m seeing over a dozen larvae corpses across the bottom edge of the side the heater is attached to. One of the berried shrimp (can’t see any others) appears to be shedding her eggs. Can’t see many adult shrimp, but they seem to be moving around slowly, relatively normally. A couple of snails and baby shrimp visible.

This is horrible. My hermit died a few weeks ago due to underfeeding which conversely motivated the shrimp to breed, but now this larvae apocalypse?

I’m going to remove the heater regardless, but could that have somehow killed them? Maybe my hand was dirty or I agitated them a lot with all of the disturbance putting in the heater? Don’t see any adult corpses, so appears to be dead larvae and shedded eggs.

Is it worth trying to remove all of the small bodies to avoid ammonia spikes?

Pics show a cluster and another few scattered around. They’ll be hard to suck out since they’ve fallen down into the rock crags.

[MrsT]

Omg shocking!
Though I can't give any solution to this, my mind came to a few possibilities:

1) Heater faulty - I once got myself a cheap heater and it burst in my tank, everything dead inside.

2) Heater is not for stagnant water. - Still water in the tank was not circulating resulting only area that closer to heater got warmer and end up too hot for them to handle. it's possible that it kill those larvae that close to certain degree. By this means, you may still got survival that hides in the opposite corner far away from heater.

3) Maybe something got into the tank.


By right supershrimp can handle wide range of temperature given that they survive in Hawaii with 2 seasons changes. I think they can still survive even without heater. As long as it's not place outdoor when snowing.

This is really strange as I saw a few video clips with heater in their existing opae tank, they have no problem with it.
There is no way to suck out dead larvae / babies with the live ones inside. You can leave it be or you reset the whole tank.
Meaning transferring the live ones into another quarantine tank and reset your existing one.

Another shortcut would be transferring the live one in a bucket while you siphoned out the dead ones and change a certain percentage of water

[Mustafa]

You don't just have dead larvae in there, you have dead shrimp too. Are you sure the heater is the only thing you changed? Have you been feeding more recently, or just a lot the entire time? Any new decoration?

Having said that...as I have written in another thread, unless your temps go down to the 40s (under 10 degrees celsius) for a prolonged period of time, the shrimp will be just fine and have no problems. I've written about it in two places (in addition to the many times in the forum) right here on this website:

https://www.petshrimp.com/set-up-a-supe ... tructions/

(in the "HEATER" section)

and:

https://www.petshrimp.com/supershrimp-s ... formation/

(in the "Temperature" section)

As I always say...if you guys just leave the tank alone after following the instructions on this website and literally do *nothing* everything will be just fine. I promise! In any case, take that heater out and just leave the tank alone. Things will fix themselves.

[shrimpy4]

Hadn’t fed them for months, heater seems to be the only new addition to the tank that may have led to this.

In the pictures those show the just post-larval juveniles that had also died. But today I’ve now counted 8 adult shrimp that have died. I have no idea what could still be going on in there. Temperature stays in the low ‘60s on its own.

There’s still a few living juveniles swimming around, and two new larvae from one of the last berried shrimp. Many of the adults are hidden away, there’s very little movement in the tank. There should still be about 30+ adults hidden away, and whatever has been killing the shrimp has hit the larvae the hardest, then the juveniles, and now adults are dying.

Any recommendations? I’m going to leave the adult bodies in there for now too unless I hear otherwise.

Edit: one other possible irritant unrelated to water quality, I do have two cats that have been known to jump on the cover of the tank. Cause a lot of disturbance to the water, but I haven’t seen them do it in months. That would just jostle the tank a lot, they can’t get in it. Otherwise, there’s no longer a hermit crab in there since he died, but I can’t imagine he was helping to maintain any sort of water quality balance.

[Erlina _rusli]

Is there any decoration that emits toxin after a while? Or thecats brought in some pollutant into the water tank?

[shrimpy4]

Don’t believe so. Only items are store bought substrate, lava rock, argonite rocks, and old coral. There’s a good deal of Mustafa’s chaeto, but I don’t think that would leech enough nutrients.

Oddly, most of the bodies are clustered in the corners of the tank.

[Mustafa]

If you keep seeing dead shrimp go ahead and make an immediate 80-90 percent water change. And take the heater out. Then leave things alone. No matter what the reason for the deaths the water change should fix it as obviously something is in the water that's killing them.

[shrimpy4]

So I performed the water change. Never done it before, but basically just premixed 1.010 SG water, and removed about 3 gallons from the tank. Tank is 5 gallons with well over 1+ gallon taken up by decorations, so must’ve been close to or more than 80%.

A few of the shrimp I thought were dead are just in death throws; not moving unless disturbed and then kicking their legs until they roll over. Was able to remove 3 dead adults. Now there’s 2 dead adults I can see, and maybe two dozen larvae and juveniles. Graveyard, it’s depressing. Oddly enough, whatever affected the water also brought the snails out. I thought there was only one or two left, but now there’s five crawling around the sides.

Already I see more shrimp moving around the substrate; not frantically but more like they used to. One berried still. And the larvae survived the water change! I sucked him up once with the cup I was using, but saw him and dumped him back.

Fingers crossed we’ll see how they do in a day or two. Heater has been out for a few days (when I first posted about it), but I wonder if it was leeching something into the water. A chemical or battery acid? I checked the PH and it was normal, but it was just a strip so not very accurate.

[shrimpy4]

Well, so since I performed the 80%+ water change, things seem to have stabilized. There are still a lot of dead larvae and juvenile shrimp tucked into the substrate, and I can't tell what happened to the eggs of the shrimp that was still berried. Could still be carrying them, could have dropped them, or if they hatched they may have died immediately.

Of the adult shrimp (used to be probably close to 40+), I lost about 7 or 8 that I'm sure of. There were three adult corpses I couldn't remove easily, but looks like they've been devoured or completely broken up.

Will keep an eye on things. Their movement around the tank is much more typical, and there are still at least two juveniles visible. Still really bummed out by whatever caused such a huge die-off, and hope things can completely return to them breeding like they were so much before. That'll be the real indication to me that the tank's actually recovered.

[Mustafa]

Your tank will be fine over time as long as nothing enters the closed system and overloads it. This just goes to show again that we all need to be very careful when dealing with these tanks so that we don't introduce anything that could either poison the shrimp (ammonia via too much organic material and food, household chemicals)or deplete their oxygen supply (excess food) or both. Just keep it as simple as possible and everything will be fine.

[shrimpy4]

Well, been out of town for almost 2 weeks and came back to find about 18 floating larvae, so looks like a couple of new berried shrimp have hatched. They must’ve been berried during the crisis and stayed hidden. Glad to see these little guys doing alright.

Tank wasn’t getting much light, so the macroalgae has wilted and strands have started to break down and die. Starting keeping an LED on during the day to keep it from dying off completely. Hopefully that doesn’t affect the larvae negatively in any way. The larvae seem to like hanging out under the LED.

[JoanToBa]

Nice!

[Mustafa]

Good to hear/read that your shrimp are doing ok and even breeding again! Your light isn't really pink like that, is it?