Foodchain

[dj.simpson]

Hi all,
I'm trying to recreate as much of a temperate marine ecosystem as possible in 250ltrs (55gal). Some things are working (healthy live sand bed and anenomies breeding like rabbits) , somethings are not (seaweed dies or gets trashed by creatures and fouls water). Currently I'm actually using bait to feed those creatures big enough but am wanting to wean them off this and replace it with something naturally occuring in their everyday environment. I live across the road from where i dive so i collected somethings that I thought might be appropriate. For my short finned eel, I got some crabs and for the fish i netted a swarm of shrimp. Both of these were a fail, more than a fail, the crabs are mean (really nasty) and trash my seaweed. The shrimp are too quick to be eaten and now seem to be gathering in numbers and organisation (it is possible they plan revenge). They are actually very efficient cleaners but I would've thought they'd be a great self sustaining food supply, wrong.
My question is, what live food can i introduce? Sea monkies were good but they were all gone in seconds, I need something that, after sufficient seeding, will sustain itself thus supporting the next creature up the food chain. Net result obviously being less artificial interference with the ecosystem.

 

[Len]

Unless temperate captive systems are very different then tropical systems (and I don't think it is), it'll be impossible to set up a self-sustaining food chain in a 55 gallon. Your higher order predators will consumer faster then anything can reproduce in that small of a volume. If you added a big refugium, that may be a different story. I would just keep up daily feedings to your temperate fish (silversides, mysis, etc.)

 

[Saltlick]

Len is right, and in general, in a captive small system, they will not only eat, but likely eat more than they need.
Piggie-style. HOWEVER, it is very likely you could succeed if you think small. Instead of netting fast moving
shrimp, turn over rocks and collect what scurries for cover, amphipods (scuds) Collect seaweed in a fine mesh
bag and once you are somewhere where you can stand up, shake the seaweed vigorously into your net bag to
collect the small creatures. Either keep the seaweed for maybe an outdoor aquarium or leave it where you found
it. Only the tiny creatures that will be able to hide in your tank will be able to reproduce in a sustainable fashion.
Beware however that you might get more creatures than you want, i.e. parasitic isopods and the like. But if you
are setting up a "Melbourne's finest"- style tank, they have to deal with that anyway. I think the fish will eat the
smaller amphipos and the ell will eventually deal with the shrimp. Crabs are fine, provided you crush them and
feed them to the eel that way. For the most part, the only good aquarium crab is a dead aquarium crab, at least
the estuarine varieties. Do some dip netting in the marsh areas and get your self some of the grass shrimp that
I am sure you will find there. Run your net from the bottom of a clump of grass to the surface and out. You should
fine a more appropriate food source there as well. Most of the best food for ocean fish is nurseried in the marsh.