Ghost shrimp

The latest addition to my tank is a small group of Ghost shrimp (Palaemonetes sp.). I like the idea of having shrimp in my community tanks, and Ghost shrimp are both large enough to coexist with the fish I have, and cheap enough that I can afford to keep them in conditions where successful recruitment of offspring is unlikely.

Fish are most interesting if they're are active swimmers. The appeal of shrimp, on the other hand, lies in the fact that they don't move much. They tend to spend much of their time in one spot, feeding on whatever detritus or algae is at hand. Being translucent, Ghost shrimp may not be the ideal aquarium shrimp, but they make up for this limitation by being cheap enough to stock at relatively high densities. They also happen to be large enough to coexist with the fish I have in my community tank - Glowlight tetras, imperfectly identified Blood tetras, two species of Corydoras, some Otocinclus and several kuhli loaches.

I decided to use my algae issues as an excuse to add a few Ghost shrimp to my tank. After all, there tends to be a relationship between species diversity and stability in ecological systems. I can't say it helped (I would honestly be very surprised if eight shrimp - or fewer - could make any change in a 55-gallon aquarium, especially given less than a week to work at it). Not to mention that they are supposed to feed primarily on algae.

After a week there are between five and seven survivors. I found one shrimp dead the morning after I purchased them (the smallest of the group); I'm hoping the rest of them made it. I saw five of them together yesterday - that sets the lower limit on the number of survivors - but generally I only see two or three of them at a time.

Palaemonetes paludosus, the eastern Grass Shrimp.
Public domain image. Original image by Joseph Stansbury Rosin, cropped and sharpened by Kazvorpal.

The Ghost shrimp available in pet stores in the US appears to be Palaemontest paludosus, the eastern or riverine Grass shrimp. One of the most interesting things about these shrimp are that they apparently dig quite extensive burrows. Via The Aquarium Wiki

The Ghost Shrimp burrows to feed and digs its two to three foot deep burrow with the claws of the first and second legs. It uses these legs to draw the sandy mud backward and collect it in a receptacle formed by another pair of legs. When the receptacle is full, the shrimp crawls backward, reverses itself in a special turn around chamber and then deposits its load outside. The burrows are not permanent. A number of branches and turnaround chambers are found in the burrows and they have at least two openings to the surface. The shrimp use their pleopods to produce some circulation of sea water through the burrows. The pencil-sized openings of the burrows are typically in the middle of little piles of sand or sand with small pebbles.

This would suggest that tanks with coarse gravel bottoms may not be ideal for keeping these shrimp. It might also explain why I rarely see more than one or two of them at a time. It does seem hard for me to envision how such a small shrimp would build and maintain such an extensive system of burrows.

Female carrying eggs. Public domain image courtesy Vlad at The Aquarium Wiki.

Juvie shrimp

My 2-month-old Cherry red shrimp appear to be pretty close to full sized but only a few of them are very red. Despite that, I noticed that at least one of them seems to be carrying eggs. I don't know for sure, but I am definitely hopeful. It would be reassuring to see them breed - the mothers of these shrimp were carrying eggs already when I got them, so I can't really claim to have "bred" them. If these guys breed, I will feel comfortable about the water parameters, and more hopeful about my ability to sustain a population.

Nineteen

Just counted 19 juvie shrimp (and that doesn't include the little dots that are still flitting around). My best prior count was 15. On the other hand, I haven't seen the last adult for several days - I'm getting a little worried about him.

Shrimp skins

After losing three of my four adult shrimp, I was rather concerned when I started finding what looked to be dead juveniles. In the first few cases, I noticed that they seemed rather thin and insubstantial, but after a while I concluded that they were probably shed carapaces, rather than dead shrimp.

That said, some amount of juvie mortality is to be expected. I'm still thrilled with the fact that I ended up with at least a dozen offspring, despite the fact that the tank was very unsuitable for shrimp when they first hatched; the initial setup included a female platy and an unprotected filter intake. On the other hand, the filter box may have provided a refuge/nursery for the young shrimp - since the filter pad was very dirty and the flow was only moderate, it might have been a perfect, food-rich environment for them. Makes me curious how well they tolerate the water flow and whether light is important for their development...

Shrimp

Last week, I lost three of my cherry red shrimp, perhaps as a consequence of a large swing in temperature. I still have one of the original adults (a male, presumably) and at least a dozen juveniles (the largest of which are almost the size of the male).

Over the last few days I have been seeing some tiny organisms swimming around in the tank. Initially they were just at the limits of my perception, but by today they approaching a half a millimetre. Are they some sort of small crustaceans which were introduced with the plants but are finally reaching population sizes that allow them to be noticed, or are the baby shrimp? It's possible that one of the females was carrying eggs that hatched before she died - but I'm surprised that I would have missed something like that. Of course, it's also possible that one of them was carrying eggs when she died - and that some of those eggs managed to survive untended.

I suppose I shall find out eventually whether these are shrimp or something else. Shrimp would be cool. A spontaneous Daphnia population would also be kinda cool.

Shrimp mortality

I found two of my cherry red shrimp dead today. While I'm sadden by their deaths, I am more concerned by the fact that I don't know what killed them. Was it just chance? I doubt it - one death at random wouldn't surprise me, but two seems to be a bit much of a coincidence. My water parameters seem to be ok. The only real notable change is the weather - temperatures fell from about 27°C/80°F on Monday to about -3°C/27°F on Tuesday night. While I have a heater on the plant tank, it lacks a cover (and the cat pushed the shade away from the window, which probably exposed the tank to draughts).

So is it the weather, water quality, a pathogen, or just coincidence? I wish I knew.

Shrimp

I counted at least a dozen baby cherry red shrimp yesterday. The largest of them is 11-12 mm long (plus tail).

And in the main tank, I have seen a ghost shrimp twice in the last couple days. That was quite a surprise - I didn't really think any had survived the initial introduction.

Baby shrimp

I saw at least one baby cherry red shrimp in the plant tank yesterday. It was pretty cool - about 3 mm long. It isn't ideal breeding habitat for them though - between the filter and the pygmy corys, I don't think the survival probabilities are too high. The tank is good overall - it's densely enough planted by now there would be adequate hiding spaced from anything but pygmy corys.

I'll see what the survival rates are like. Hopefully I have at least one male among the shrimp, and they'll breed again soon. It takes about 28 days, apparently, after the eggs are laid. We'll see what happens next.

Cherry shrimp

I have been intrigued by shrimp for a long time. Petsmart always has lots of ghost shrimp, but Lindsay has never liked transparent organisms, so I was really glad to come across Cherry shrimp in Houston. They weren't cheap, but they are supposed to breed readily. I'm hopeful - I love shrimp in aquaria.