Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Temporary holiday aquarium

Holiday aquarium
Holiday aquarium

Most of us are restricted to rock pooling while on holiday. If this is going to be your only chance to catch some stock for a rockpool aquarium you need to have a good method of maintaining the fish that you caught at the beginning of the holiday. Otherwise your collecting is going to be restricted to anything that you catch on the last day of the holiday and if the weather turns bad on the last day...

If like us you are a keen photographer then like us you will have soon realised that wildlife by the seashore doesn't really like to cooperate. This is where setting up a small temporary aquarium can really pay dividends and this is how most of our photos used on this site were taken.  We set up a 36"x 12"x 20" aquarium to make it easier to observe and photograph some of the various creatures we found down at the beach while rock pooling.

The first thing we did was to find a suitable stand for the tank. Fortunately for us, the cottage we were staying at had a very nice solidly built coffee table in the front room that we quickly appropriated. We relocated the coffee table so that it was close to an electrical source for the lights and filter. We didn't need a heater because they are temperate fish that could withstand a wide variety of temperature changes in a short period of time.

After finding a location for the stand, we covered the back and sides of the tank with a black aquarium background to hide distracting wall colours and to help bring out the colours of the fish.
Next we set up the filter. We used an Eheim 2012 internal power filter.
However because we weren't going to have any time to cycle the tank, we used a poly filter pad to remove organics from the tank, including ammonia.
The Eheim filter came with a sponge filter that occupied the entire chamber for the filter.
In order to fit the polyfilter pad in the filter, we needed to cut the existing foam filter pad in half.
We've placed half the original filter pad back into the filter to leave room for the Polyfilter material.

Next we used an entire 8" x 4" sheet of polyfilter material in the half that was left free.

The photo above shows how much organics the polyfilter removed from the tank after just one week of usage.

We placed the filter in the back corner of the tank leaving as little room between the filter and the tank as possible to help prevent animals from hiding behind it.  In the end the animals still found a way to squeeze in the small gaps.
After we placed the filter in the tank, we placed rocks that we collected from the beach where we would be collecting the livestock from. Please check local regulations before collecting sand or rocks from a local beach to see if it's legal to do so. We made sure that we collected rocks with some algae growing on them to give the tank a more natural appearance and to provide a bit of food for the animals we would be keeping. From previous experience we found that rocks with a lot of loose bright green algae was a good addition because all the animals would graze from it from time to time.
Once we were satisfied with the distribution of the large rocks, we proceeded to place handfuls of sand around the rocks to help ensure that the larger rocks would remain stable.
The substrate layer was less than 1cm thick. Again the substrate was collected from the same beach as the rocks were and the substrate proved to be unexpectedly full of life as we discovered that we had unknowingly and unintentionally collected a worm pipefish and a couple very tiny shore crabs in the mix! These weren't added to the tank until later.
After the substrate was placed in the tank we started filling the tank with artificial salt water, name brand D-D H2Ocean Natural Reef Salt. We tested the salinity using a refractometer to ensure the water was at full ocean strength of 1.025 SG.

We covered the tank with a condensation tray to prevent escapees, reduce the amount was water loss through evaporation and as a convenient place for the single fluorescent tube light to sit.
We left the tank to sit over night with the filter running to clean out the water and ensure that all the salt was mixed thoroughly before adding any sort of livestock. We ended up using some of the background material as a reflector as well.

Introducing new stock

This can be a real minefield because there is so much to consider. Almost all the fish and inverts that we collected settled down and began behaving quite naturally and feeding surprisingly quickly, often within an hour or two. Mullet fry did seem to get a little stressed during capture and transport but once in the tank they became some of the boldest feeders and would accept flake food directly from our fingers after a day or two. But it is important that the fish aren't kept in buckets ect any longer than is absolutely necessary or losses may occur.
Compatibility is the other big issue. Most rock pool inhabitants eat other rockpool inhabitants if given the chance and some will even do this immediately after capture and while they are in a bucket, something I have witnessed for myself.

If you feel there is going to be a problem with a new specimen, a scorpion fish for example, then release the smaller potential prey fish before adding the new larger predator. While on this subject, if like us you only want to photograph the specimens it is important that they are released in good health and back to the very same location that they came from, this means the very same rock pool. Don't mix fish from different locations if you intend to release them afterwards, although a small risk, the practice could result in the inadvertent spread of disease.