Posts Tagged ‘distilled water’

The Post – A Fiddler Update – Water Issues and Decreased Numbers

March 7, 2008

I am not sure that things in the nursery tank are going well. A sudden reversal in fortunes over the last day or so. Very decreased numbers of babies. In fact, this morning, it’s hard to tell if there are any left. The water got cloudy, like an algae bloom, and the nitrites spiked high and even a touch of chlorine showed on the dipstick, odd since I use distilled water. So the chlorine is coming from tank conditions, not the water I used. Some thoughts:

I am not sure if the decrease in numbers is:

1) Normal? They cannibalize each other.
2) High nitrites?
3) Touch of chlorine?
4) Wrong food?
5) Too much or not enough food?
6) Salinity? Are the science articles wrong and should I have left it brackish?

Water quality:

It started out that the water would get cloudy for a little while after I put food in the tank. Then it would return to being clear. Now, however, it’s cloudy all the time. I replaced 1 gallon of water last night (still “marine” at 1.019), and I added buffer to raise alkalinity for them to have enough calcium to molt. I also added Prime to get rid of chlorine and decrease nitrites. I succeeded with raising the alkalinity, and eliminating the chlorine. Nitrates are still in the “okay” zone, but nitrites didn’t drop.

This morning the tank is still cloudy. I will recheck parameters in a little while, and probably replace another gallon of water. I hate to do that because if there are babies left, I am most likely pouring some of them down the drain with water I tank from the tank. I do pull the water from the side of the tank where the babies did not hang out much, but still. Nothing to be done there though. a.m.

It occurred to me this morning that maybe the phytoplankton was either a bad idea or I just gave too much. The phytoplankton is alive. I noticed the water I drew off last night had a greenish tint. That means the phytoplankton, which is PLANT plankton, and alive, may be blossoming, in fact, maybe it’s a phytoplankton bloom in the tank. Given it’s not the open ocean, but a closed environment, the bloom, while successful in generating more food for the babies, maybe too much of a good thing in an aquarium. If too much growth, is it raising the nitrites and killing off the babies? I am wondering if I should have left the food at “Small Fry” and maybe the ground up krill and not added the phytoplankton.

I will also put a sample of the water under my “precision” microscope later to see if in fact the water is jammed with plant cells.

I will update on the results of water change, microscope viewing, and repeated parameters later, as well as whether it looks like there’s any babies left.

Live and learn. As my husband says, “Next time”….I think there’s always things we can do better. AND, once this experiment is over, we’re going to leave that spare tank up and running empty so it can settle out with a matured nitrogen cycle. Stay tuned for updates.

The Post – What to Feed the Babies and How Salty Should the Water Be?

March 1, 2008

Just a reminder that coming up over the next week, the next few installments on the journey of my Under the Pier novel. I had to take a break from those for taxes, actually finishing some more chapter revisions, and of course, taking care of the “grandchildren.” But stay tuned. More to come on Under the Pier.

Re the grandchildren:

What wonderful goings on! Soooo many little black dots in the nursery and they are definitely swimming around. Many are hiding out in the shadows of the live rock caves. So tiny and already they know to hide and avoid “predators.”

I am feeding them three times a day with a mixture of ground up mini-freeze dried krill, some ground up flake food, a few drops of the liquid Small Fry baby fish food, and a little distilled water mixed in. We shall see how it goes. And no, I am not grinding the mini-krill with my husband’s lovely stone mortar and pestle that he uses for grinding up herbs and spices in the kitchen!!

Regarding salinity – it’s a tricky call. While Uca minax, which are the type of fiddler crabs I have, are seen furthest up the estuary in areas of lowest salinity, there seems to be evidence that for at least the first two weeks of their larval development (zoeae) , they actually survive and do better at a higher salinity. However there is also evidence that for the next (megalopae) stage to metamorphose into crab Stage 1, this species does best with the lower salinity seen in the upper estuary environment that the adults live in. I will post more information tomorrow including the links to the two papers I found today on this subject. Long story short today though, is that zoeae of all the species of fiddler crabs, seem to need a couple weeks of “being at sea,” hence higher salinity.

I’ll also explain about the three species used in one of the studies and how their selectivity for salinity levels puts them in different spots in the estuaries and thus probably keeps them from competing with each other for resources and food.

Also to come – I dug out the small microscope I had as a kid and will pick up some microscope slides. So to follow, descriptions of babies, under the glass.

A couple of other notes – courtesy again of my engineer husband. He noted a bunch of white things all over the gravel and wondered if the babies had already molted. Maybe they have but these white dots were too big and irregular in size for baby shells. I believe it’s salt crystals that didn’t dissolve in the water before I added it. I added more water to bring the salinity up closer to a marine environment. I started at 1.010 (brackish) when they were born and over the course of yesterday raised the salinity first to 1.012, then by last night 1.015. Today I’ll finish raising it to 1.020. Then in two weeks I’ll bring it back down to 1.010-1.012, the optimal range for Uca minax adults.

Sand. Again, my husband was watching the babies swim – it is amazing to see these tiny things whiz around the tank – but he shined a light to see if they would follow the beam. The article I posted in yesterday’s gift mentioned that the babies will go to the light. My husband didn’t see evidence of that, but what he noted was that many little babies had worked their way down between the gravel bits, all the way down to the bottom of the tank. Unless they figure out how to get back up to the water, they’ve had it. Now let’s face it. Their parents had a brain the size of a pinpoint. How large a brain do you thing babies the size of a pinpoint have? So the odds of them getting back to the surface are not good. I said “evolution at work. Anybody who tunnels down in the gravel probably won’t live to reproduce. ” My husband noted that gravel is less than optimal for this (engineers talk like this by the way, things are optimal, less than optimal, sub-optimal 🙂 ).

The real important point though was his next comment: “The NEXT time we do this, we should use sand.” There you have it folks. My husband has fallen in love with the fiddler crabs. In all truth, he has. He watches them, thinks about how to make their lives better, anticipates the babies getting ground up in the water filter…..those babies are lucky to have him!!!

Anyway, stay tuned for the links on those two articles about optimal (yes, OPTIMAL) salinity levels for fiddler crab larvae.