It’s been more than four months since the Alternanthera reineckii ‘Rosanervig’ got planted in the Fireplace Aquarium, and whilst it seemed to be doing well initially, after 11 weeks things weren’t looking so great.  I thought lack of light from overgrowing Bucephalandra caterina might have been contributory, so I did a massive epiphyte trim to restore light to most of the tank.  That had very positive effects on the Cryptocoryne wendtii ‘Flamingo’ but didn’t really improve the alternanthera.  There were floating fragments of what looked like otherwise healthy Rosanervig leaves and I have from time to time noticed some suspicious interest in the alternanthera from the amano shrimp.  Some surveys of the interwebs suggests that amano shrimp eating alternanthera species is a known thing which could explain the observed damage.

As an experiment, I have shielded the top of one of the Alternanthera stems inside a mesh bag.  The aquarium denisens haven’t particularly noticed, although I did see a cheeky amano shrimp sitting on the bag – it scampered when I tried to take its picture.  We’ll do an updated report after a while to see how the bagged plant compares to its non-bagged counterparts.

There’s an interesting new inhabitant in the Shrimphaus, what looks like a spontaneous mutation in the bloody mary shrimp lineage.  Bloody mary shrimp are generally a solid translucent red throughout but this little fella (I think it’s a boy) is mostly clear and colourless, except for a red head, red stripe just above the tail, and one red horizontal back segment.  This is the “rili” pattern, and is reasonbly easy to find in red cherry neocaridina shrimp, but there isn’t much information on ‘bloody mary rili’ shrimp.  The eyes seem to stand out a lot more as well.  I think this is because in the usual bloody mary shrimp the eye region surrounding the black pupils is reddish pink, whereas this googly eyed individual has completely white surrounding tissue.

bloody mary shrimp
“regular” bloody mary shrimp

Bloody mary neocaridina shrimp have a reputation as being reasonably genetically stable, so this seems a little unusual.  I’ll keep a look out to see how this one develops – I’m not actually certain it is a bloody mary shrimp – and whether any more different and interesting mutants come up.

Particularly after a water change, the shrimp like to collect on the river run shelf.  I’m not sure what they’re after here, but this is a consistent behaviour of theirs.  This is the kind of thing you’re not going to be able to observe without a shallow flowing water component to your shrimp habitat – something which I suspect is pretty unusual.  They also like to sit in the flow generally, but the water change seems to really get them going.  Others have seem similar behaviour from their shrimp during water changes.

Cherry shrimp generally stay in the water

Here’s an interesting example of a bloody mary shrimp (Neocaridina davidi) lifting itself out of the water.  Fortunately, they don’t do this very often and are sensible enough to get back in the water directly.

Three weeks after the first sighting of a new baby shrimp we seem to have arrival of the next crop.  These guys are really tiny which does suggest the earlier one had been hiding out for a week or so before debuting.  There was a 50% water change today – the usual story with EI dosing – and I was a little concerned the new baby shrimp might get inadvertently changed out along with the water, but they seem to have hung on well and are none the worse for wear.  The successful shrimp breeding suggests we may shortly be inundated with shrimp in the Shrimphaus, but we’ll worry about that later.

Even newly hatched bloody mary shrimp are red

Even the tiniest of these new bloody mary shrimp have an easily distinguished red colouration.  So far the colour has bred really true, which is pretty typical for reports of bloody mary shrimp.  I saw an interesting video where a guy with a pretty normal looking bloody mary shrimp tank went and did an actual count during some rescaping that came in at 600 shrimp in a 5 gallon tank.  That’s about the same size as the shrimphaus!  Everything was looking happy and healthy there so maybe overpopulation isn’t such a concern after all.

Unintentional yet still welcome residents of the Shrimphaus, copepods are a form of zooplankton.  Like their much, much larger relatives the shrimp, copepods are also crustaceans, and also have ten (?) legs, an exoskeleton, the whole works.  Copepods tend to be sub-millimetre in length, whitish looking, and capable of very rapid jerky movement covering several centimetres at a time, making them the fastest animals on the planet (in terms of body lengths travelled per second).  Happily, copepods eat algae from the water column so are members of an aquarium clean-up crew.  They are a highly nutritious food source for fish, but I don’t think the shrimp eat them.

In the pictures above, both copepods are photographed at 10x optical zoom.  Both are “heading” to the upper right.  The female has two egg sacs to both the right and left of the bottom bit.  The male? copepod doesn’t have these, but that might simply be a female that doesn’t have eggs.  These two were resting on the surface of the glass; the ones swimming around in the water column don’t photograph very well…

Copepods are abundant in the Shrimphaus but I haven’t ever noticed them in the Fireplace Aquarium, either because they were never introduced in the first place, or because the fish do a super-efficient job of keeping the population down.  I might try a water transplant from the Shrimphaus to the Fireplace Aquarium at some point to cross-introduce these little guys.

There’s a new citizen in the Shrimphaus!  Recently a juvenile bloody mary shrimp has started openly exploring.  It seems strange that there is only one so far, but there was a mother shrimp that dropped most of her eggs and maybe this is one she held onto.  The new shrimp has already successfully moulted and has been touring the slate and plants in the Shrimphaus.  I take it as a good sign that the shrimp overall are happy and healthy.

The newcomer first showed up about a week ago, which would have been around 6 weeks since the shrimp first went into their home.  If I had to guess based on neocaridina lifecycle, this youngling has been hiding out for a couple weeks before debuting.  I do think there are some other females in there with eggs so there may be some younger siblings on the way as well.

Shrimp like to hang out upside down

The shrimp seem to enjoy hanging upside down from the under surface of the river run.  I don’t know if this is a practice that ordinarily goes unobserved, but it’s a pretty common sight in the Shrimphaus.  In the photo above there are three resting upside down (juvenile on the far right) and one more slightly out of focus right-side up sitting in the river itself on the top of the slate shelf.  Sitting in the flow of the river is something the shrimp also seem to enjoy.

Following on from the disastrous experience of adding new cherry shrimp to the Fireplace Aquarium I decided to give the shrimp their own aquarium with no predatory fish!  I built them their own customised Shrimphaus and after a couple weeks of equilibrating the water chemistry and biology I added some Bloody Mary shrimp sourced from Pro Shrimp.  They all arrived alive and in good shape.

Drip acclimatising new shrimp

Shrimp can go into shock when their water parameters change suddenly, so it is recommeded to get newly arrived shrimp used to the new water slowly by adding the new water dropwise over several hours to a temporary shrimp holding container.  When the holding container is full, remove half the water and continue the drip.  After three of these cycles the shrimp will be essentially in the new water and can be safely added to the aquarium.  The acclimatisation setup was easy to rig and went smoothly.  The shrimp never appeared distressed and when added to their new home went off exploring straight away.

Shrimp keep plants clean

I had noticed the beginning of some type of black algal growth on the plants but the shrimp went after that and cleaned it all up.  In this low-tech set-up the plants will grow slowly so shrimp keeping it nice could be important.  Amano shrimp are well known for devouring algae and it’s nice that the cherry shrimp behave similarly.

Bloody Mary shrimp colouration

Although both Bloody Mary shrimp and cherry shrimp are the same species, Neocaridina davidi, and both are red, they are red in a different way.  With traditional cherry shrimp the shell (carapace) is opaque and contains the pigmentation, whereas with Bloody Mary shrimp the carapace is transparent and the interior of the shrimp is a smoothly pigmented red colour.  Apparently this comes from a heritable mutation common to Bloody Mary shrimp, Black Rose shrimp and Chocolate shrimp.

One, maybe two, of the shrimp are much paler in colour than the others.  Are these still Bloody Mary shrimp?  They have the transparent carapace and pinkish undertones so seem similar.  In some shrimp females tend to be much more strongly coloured than males, but that isn’t well known with Bloody Mary shrimp.  We’ll see how these all develop over time.

yellow goldenback shrimp hiding in marsilea
Hiding in marsilea

Neocaridina davidi are small freshwater shrimp and very popular for tropical aquaria.  These come in many different vibrant colours, most commonly a bright red usually referred to as ‘cherry shrimp’, but they can also be blue, orange, chocolate, white, black, green and several with alternating block patterns of colour.  Looking some something that would be easy to spot, I picked up seven bright yellow goldenback ones from Pro-Shrimp.  As is usual in the trade, there are no official designations and other names for these include Yellow Shrimp, Yellow Sakura, Yellow Fire Neon, Super Yellow etc.

I wasn’t sure how well live shrimp would travel in the cold weather, but they all arrived in just fine condition.  Although neocaridina can live in just about any type of water conditions, they can go into ‘shock’ when those conditions change so there is a drip acclimatisation method for getting them gradually used to new water chemistry.  I confess to having done a somewhat abbreviated version of this with maybe some slight trauma, but haven’t noticed any casualties.

I thought these bright yellow shrimp would be easy to spot, but when they’re hiding they are not!  There are lots of great hiding places in the Fireplace Aquarium including a quite dense carpet of Marsilea hirsuta on the right side.  Word is shrimp can be quite shy for days or even weeks after being introduced to a new environment.  Usually I don’t see any at all but I did at one point several days after adding them see three at the same time so I’m pretty sure they’re mostly in there somewhere.  None of the fish or the amano shrimp either have ever taken any notice of the new yellow shrimp arrivals.

I wanted to get some more liveliness in the Fireplace Aquarium, but I’m cautious to not have excessive bioload in the tank where adding more fish could be questionable.  Shrimp are the perfect choice since they are ominvores and graze on detritus/biofilm without adding much (any?) bioload.  Neocaridina are reputed to be prolific breeders so we’ll see what happens to the population even though I’m taking no measures to attempt to optimise the water conditions for shrimp breeding.

Fish ate all the yellow shrimp!

Well crap!  At first it looked like everyone was getting along, but then I noticed some very suspicious tear-the-shrimp-apart behaviour from the barbs particularly.  I did then see what I think was a shrimp being torn apart; I think the barbs start it and then the rummys join in once the shrimp is pulled into the open.  Now there are none left; I’m pretty sure they’re not simply hiding.

I think this is a size thing.  The neocaridina as received were quite small, on the order of 1 cm or maybe even a little less, which I suspect triggers the “this is food” instinct in the fish.  The amanos however have always been completely unbothered by the fish, but they are also quite a big bigger.  Even the smaller male amanos are probably getting up towards 2 cm where I guess they can take care of themselves.  I might try some neocaridina adults to see if that flies.  Consensus on the interwebs seems to be that other than the completely benign otto catfish, all other fish are a risk to shrimp in at least some degree.

MOAR CATFISH!!!

Otocinclus catfish
Otocinclus catfish

Originally there were five or six otocinclus catfish in the Fireplace Aquarum as part of the algae cleanup crew.  These are cute but sensitive little critters and I suspect that early unstable tank water parameters contributed to the gradual yet early demise of all them except one.  Ottos are social and like to be in groups so it didn’t seem right to have just the one remaining.  Today the local fish store had a restock on ottos so I picked up five more.  They acclimatised well (no casualties) and have definitely upped the peppiness level in the aquarium.  They seem to enjoy playing in the current from the powerhead because they could hide out in the more sedate regions of the tank but instead they’re upfront and active.

Ottos keep plants clean

12 day update and all the new ottos are doing well.  I think they do a pretty good job of polishing the green algae off of the lower levels leaves of both the Ludwigia palustris and the Lobelia cardinalis ‘Dwarf’.