Native marine aquaria are pretty scarce. Little information exists on how to be successful in maintaining healthy coldwater marine systems in domestic aquaria.

Hopefully this record of my failures, triumphs and ideas will assist others interested in keeping some of our fascinating, beautiful and often little known sea denizens in aquariums.

Sunday, 29 August 2010

Collecting Specimens

Probably one of the best things about keeping native marines is going rockpooling with the kids and catching all sorts of exciting fauna to take home and study. We use a couple of 15 litre buckets and a variety of nets,

I only take home the creatures that I know will be suitable for a community reef tank. Sea scorpions are fascinating, easy to catch, rather beautiful in their own way but will swiftly decimate the rest of the inhabitants. Shanny are great pets, intelligent, lively, comical and very easy to keep - but they will make short work of interesting and useful creatures like shrimps and hermit crabs.

A couple of years ago I caught a shoal of 8 mullet about an inch long and also at the same time in the same shoal a tiny bass. Within a year the bass ahd grown to 6" and eaten everything else in the tank, furthermore this voracious predator generated such an amount of waste that water quality began to deteriorate so I released him back to the sea. Although the bass was a very interesting creature and looked great shining brightly as he prowled around looking for something else to eat he simply was not suitable for the tank I wanted to create.

Pipefish are fascinating subjects. But they should not be housed with snakelock anemones - they fall prey far too easily. Furthermore they are difficult to feed although mysis shrimp and rotifers can tempt them to feed they must be closely monitored and released if they dont appear to be eating.

The collecting and subsequent transport back to the tank is the most hazardous part of the whole process. Water in a bucket on a sunny day rapidly heats up, oxygen levels fall and livestock can quickly succomb. Shanny and snails are largely bulletproof - anything found in small rockpools high up on the shore will be used to massive fluctuations in temperature and salinity, but even so, its only fair to do as much as possible to reduce any stress to the animals.

Its a good idea to use a battery powered cooler in the car to transport the collection with a battery powered airstone to oxygenate the water. anything caught below the shoreline will need extra care during transport to minimise mortality.

In practice I have found mortality levels to be very low. I live near the sea and rarely take longer than an hour to get the animals into the aquarium. For me the greatest risk is immediately upon release into the tank. Frightened small fish have a habit of blundering straight into the anemones! A holding tank to allow the animals to stabilise at the cooler temperatures of the tank is a good idea. Turning the main pumps off at the time of release helps new arrivals to find a hiding place before being blasted into the waiting arms of a snakelocks.

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