Goldfish And Marine Aquariums

Gold Fish

I’ve been involved with aquariums for 40 years or more and no, I’m not going to try advising the secret of keeping goldfish in salt water! What I’m going to do is remember, if I may.

Over 40 years ago I had nothing to do with fish. What did I do with my time I wonder – well, I had two children, Michael and Peter. As is normal we ended up one day at a fair and yes, there was a goldfish stall, throw a hoop or something similar. My boys must have been good shots because we ended up with a couple of goldfish, the common variety, in a plastic bag. They had instantly joined the family and so a small plastic aquarium was obtained on the same day. Once home into the aquarium they went. Michael and Peter were overjoyed. It must have been at least a whole week before they lost interest!

So there they were, these two goldfish, in their small aquarium on a shelf. For a while nothing changed and then I added some gravel as it didn’t look natural. A while later I added a couple of plastic plants. Now things were so much better. The fish seemed to enjoy nosing about in the gravel. Guess who was in charge of cleaning and it wasn’t Michael or Peter!

Then I decided – and this I reckon is where I became doomed to my fate – the fish would be happier in a bigger aquarium, so they got one 24″ long. It came off the shelf and stood on a more solid work surface in the kitchen.

Then I decided it would be better to have tropical fish (the addiction was getting a grip). I kept standard tropicals for a while and still used plastic plants. The fish were fine.

Then I saw my first marines, this would be quite a while later, about 5 years after the first goldfish appeared. They were in a pet shop and I learned they were damsels. What colours, wow! I didn’t buy damsels once the decision had been made to keep marines; I obtained two common clowns (Amphiprion ocellaris). These were kept in a slightly larger aquarium, 30″, which sat in the same place as had the 24″.

Since that time I’ve travelled down the road in the same way that so many others have. That first small marine aquarium which was fish only became larger and as time passed contained a variety of fish. All were reasonably successful and I don’t recall any serious problems except one. This was with a juvenile emperor angel (Pomacanthus imperator) about 3″ or so in length. It was so lovely I was quite awestruck. It seemed very happy in a 4 ft aquarium which had a reef and several soft corals. Then one day I found it lying upright against the front glass. Close observation showed it was breathing quite heavily and I suspected white spot or velvet, two serious diseases with marines. As the fish wasn’t moving I was able to inspect it with a magnifying glass but couldn’t see anything. Seawater testing indicated all parameters as being fully acceptable. Strangely, no other fish displayed any symptoms. Eventually the fish died and it affected me considerably, feeling quite guilty of losing a fish that had been taken from the wild and had died in my care. I was not as experienced as I am now of course, and currently I would have investigated further.

Soft Coral

On I went in the hobby and eventually graduated to a full blown reef aquarium. The first one was built into a wall like a picture, with a sump (a 30″ aquarium). The aquarium became larger (I filled in the hole in the wall) until, calamity, we moved house. This was 10 years ago.

An aquarium was inevitable though, the one I have now is smaller than that at the previous address because of the space available. Peter kindly purchased it for me, and I made the cabinet and hood and fitted all the bits and pieces.

It’s a soft coral reef which has been running for 7 years (I know this as I keep a notebook). I love soft corals, the pastel colours and the way some of them sway in the seawater currents. It’s lit by a bank of three marine white fluorescent tubes, and two blue (actinic) tubes. The tubes are timed for a ‘dawn’ and ‘dusk’ sequence, in the morning the blues come on first then the whites, and vice versa when they go off. Seawater movement is created by two powerheads, arranged to produce the necessary random chaotic flow type. The bio-filtration was by two Eheim Ecco canister filters containing sintered glass, this could seem a bit backward to some but it worked well. Any nitrate presence was dealt with by a home made hang-on sulphur based denitrator and routine seawater changes.

The reef is constructed of inert dead rock with the name ‘Grotto Rock’, I don’t know why as it wasn’t from any grotto. The rock is very porous which is good for bacteria populations. It was excellent for the purpose with its various shapes, and many caves and crevices were formed. The reef sits on a plastic grate about 1¼” or so above the base glass. Another powerhead pumps seawater under the reef (below the grate) through a multi-dispersal pipe, which has successfully kept the underside more or less clean and of course has kept the lower regions oxygenated and prevented temperature stratification. Once the reef had been constructed the net gallonage of the system was 43.

I also constructed a hang-on anti-phosphate filter filled with a well known media, and this has operated from the beginning.

There is also a hang-on protein skimmer, a Red Sea ‘Prism’. This isn’t the world’s best skimmer but it does a sufficiently efficient job probably because of the low fish load. There could be some DOM (dissolved organic matter) that could have been removed, but perhaps it is helping to feed the corals. Let’s not get into that as it’s another subject.

Apart from various corals there are only two fish, a Flame Angel (Centropyge loriculus) and a Fijian Damsel (Chrysiptera cyanea). I believe that with reef systems it is better to under stock than fully stock (although there is nothing really wrong with the latter if done properly and growth is taken into account). This is because of seawater as it is easier to maintain at high quality with less fish. It’s a matter of personal opinion and taste. Routine seawater changes are still completed.

I have a very small DSB (deep sand bed) which is not large enough to have any particular impact on the aquarium; it was constructed purely out of interest. It is successful and, particularly at night, numerous tiny life forms can be seen. In the main aquarium quite a large number of snails are seen at night, and fortunately they are not the troublesome variety.

The canister filters are still running though the media has been removed. This happened a good while ago because I suspected the dead rock had changed to live. The rock, with all the growths on it, looks very similar to the live variety. I began to wonder about the rock as there wasn’t ever a trace of nitrate when the seawater was tested. Admittedly there was a denitrator but was it that efficient? Also of course routine seawater changes were being done.

To check I stopped the denitrator. Over three months of testing there wasn’t a trace of nitrate so the denitrator wasn’t changing anything. It remains switched off though it hasn’t been removed (I’m maybe too lazy!). Then I tested the seawater before a routine change, still no trace of nitrate. Then I left the seawater unchanged for three weeks, still no trace. So I began to remove the bio-media from the canisters, one was emptied entirely, and then the system was left for two weeks. There wasn’t a trace of ammonia, nitrite or nitrate at weekly testing. Then I removed ½ of the bio-media from the other canister, still no change. Now the final media was removed, though this made me nervous there wasn’t any change whatsoever. The rock had become ‘live’.

As the rock was porous the bacteria that deal with the toxins ammonia and nitrite established themselves on and in it, followed deeper inside by the bacteria that are able to deal with nitrate. The canisters had become redundant, though they still run to cause agitation at the seawater surface. The rock dwelling bacteria are clearly dealing with any toxins that are produced.

There’s a large amount that I’ve missed out about the journey from goldfish to a reef as there would be with other marine aquarists who have followed the same or a similar route.

The marine hobby has provided a little insight into the world of the wild reefs. I’ve had the good fortune to snorkel on many reefs in various areas and what a pleasure it was.

As time has progressed I’ve become more and more involved in the whys and wherefores of this and that. Now that experience has accumulated, looking back to the very early days with marines I have to smile and consider it was certainly worthwhile. Learning continues. I’ve found the marine hobby to be educational and it develops the discipline of patience. It’s also entertaining and fun.

1 Comment
  1. Wow, some very informative stuff you have on your aquarist blog, ive just spent the last 2 hours viewing. Learned a lot of things and just wanted to congratulate you on such a great blog.

    Keep up the great work, will be back soon and will recommend.

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