Sudden Lobster Death

Hi all, I bought a few lobsters and they were doing fine for quite a while now. Suddenly today, I found 2 (both different species) lying motionless at the bottom of the tank. Their legs are still twitching but barely, and I believe they are almost dead. The head shell (carapace) is detached from the body slightly and I can see the flesh inside. Did it die due to insufficient nutrition and it tried to moult? Or is it a lack of calcium in the water? My other lobsters are doing fine. I have 7 lobsters in my tank in total: 2 Cherax sp Blue Moons, 2 red Clarkiis, 2 Zebras and 1 red-clawed.

Anyone with any advice or solutions? Pls help, thanks!

lobsters are big tricky bro. i used to keep blue and red lobsters.... hard to keep them... they just died on me without any reasons... in the end i give up and keep to my IT, oscars, BP and aros.

The same thing happened to my friend last week. He lost 3 blue crayfish and according to him this is not the first time. The other time it happened his whole tank of crayfish was wipe out. He believe the problem lies with his internal filter as the first time he suffered a wipe out he was using that and just before cny his ehiem broke down so have to use back the same filter and the next morning three crayfish went to the gods.

if you want to have a successful breeding of lobsters, you may ask this bro Jon409. he seems to be good in keeping lobster becos once a while, he will put up baby lobsters for sale.

quite a nice and friendly bro.

Thanks bros! I managed to get two of my Zebras to breed, the babies now about 1.2 cm long. Wah very sian I lost 4 lobsters within 2 weeks, and the Blue Moons weren't cheap. I figured that it's a case of too many lobsters in the tank, because other lobsters are still doing fine so it can't be a problem with the filter. Maybe not enough calcium in the water for them to absorb and make the new shell underneath the current one so they die when they try to moult.

Interesting, I don't know they need calcium in the water for the to complete their moult. That may explain why my red crab died after he shed his shell.

Ah.. that was what I thought at first, before one of the bros here told me that they need sufficient nutrition to get their food but they also do take in calcium from the water. Having too many crustaceans in the tank will reduce the amount of calcium available for them. I've done a lot of water changes since and have bought calcium powder to dose in the tank. The coral chips I put in also seem to be eroding at quite a fast pace.

But generally I thought once they moult they're safe? Your red crab managed to successfully moult?

I'm still facing the same problem. Anyone can offer advice? Thanks!