Dreaming of Marines - Start up with Blue Damsels
My friends, the Patel brothers from South London, started keeping marines over two years ago. Their made to measure tank (1170 cm x 580 cm x 750 cm, length x width x height) fitted snugly into the alcove created by removing the metal fireplace from the chimney breast in the living room. Marine set-ups need a lot of equipment outside the tank to ensure water quality and stability. In the limited space surrounding the tank a lot of equipment had to be fitted. The outside canister filters (Eheim 3228 Thermo wet/dry filter, Eheim 2226 filter) and the UV sterilisation unit (Vecton UV15) were fitted under the tank, while the protein skimmer (Berlin Classic 25/250 gallon, Red Sea) was fitted alongside the tank in a cabinet.
In the limited space above the tank was the lighting units consisting of several metre-long tubes (3 daylight tubes and 2 marine blue tubes). The whole fireplace was beautifully and cleverly wood panelled to conceal all the equipment. Since then, some of the equipment has been upgraded, but that is another story. The tank was filled with salt water (Kent marine salt: specific gravity: 1.020 – 1.024, pH: 8.0 – 8.3, temperature: 270-280 C). Coral sand placed on the floor of the tank, the water circulation started and about a week later three pieces of living rock were added to the tank. The water parameters were tested on a daily basis
Because the aquarium is a closed environment, the wastes excreted by invertebrates and fish as well as uneaten food stay inside the tank but are toxic to life in the aquarium. Fortunately there are bacteria that are capable of converting these wastes to safer by-products. Colonies of Nitrosomonas and Nitrobacter bacteria, both of which are required for effective biofiltration need to be built up in the filtration system when starting any new tank. Fish waste consisting of feces, urine, as well as any uneaten food, are quickly broken down into ammonia. In the marine aquarium where the pH is around 8.0, ammonia is not ionized and is highly toxic to fish especially if levels reach 2 ppm. Nitrosomonas bacteria convert ammonia to nitrites which is also highly toxic to fish at levels as low as low as 1 mg/l. Nitrobacter bacteria then convert nitrite to nitrate which are much less toxic. The bacteria are aerobic, requiring an oxygen-rich environment to flourish. The nitrate accumulates in the tank, unless there are lots of plants in the tank, but can be removed by changing the water. The series of oxidation reactions carried out by these bacteria are commonly known as the nitrogen cycle.
Many of these bacteria needed for the elimination of waste are already present in the living rock but need to be established in the external filtration media which are designed to provide a huge surface area for the bacteria to colonize. The bacterial colonies cannot be established in the filtration system unless they have wastes or uneaten food to feed on. The usual method to speed up the process is to introduce a few hardy fish into the aquarium and to feed lightly. Better still, many experienced hobbyist advocate not add any fish at this stage but just add very small amounts of flake food to feed the bacteria. Within a day or so, the ammonia levels in the water start to rise sharply, which the Nitrosomonas bacteria start to utilise as a food source. The bacteria multiply and spread to the filter media, continuing to feed on the ammonia which will start to fall. Meanwhile the nitrite levels will be rising more steadily, causing the naturally occurring Nitrobacter bacteria to now kick in, feed, multiply and colonise the external filters. Within two weeks both ammonia and nitrite should be virtually zero, providing there has been no overfeeding.
The Patels monitored water parameters closely using test kits for ammonia, nitrites and nitrates but two weeks after the addition of the live rock, ammonia and nitrites registered zero. There was great excitement as it was time to bring in the first few colourful marine fish to liven up the tank. But what fish to add? The fish that are needed to prime the aquarium need to be hardy and relatively cheap, in case of mishaps. The Patels were also looking for colour and personality in their first marine fish. They settled for five Blue Damselfish, Chrysiptera cyanea, which they introduced into their marine tank. These small fish quickly settled in and seemed to revel in the vastness of the large tank. The damsels eagerly accepted the small amounts of food consisting of frozen brine shrimp or dry flake food that was offered twice a day.
Looking at Damsel fish
In the wild, damsel fish have a wide distribution in the tropical and sub-tropical coral reefs around the world, particularly in the Indo-Pacific areas. There are over 200 species of damselfish all of which are active during the day and sleep in holes in the coral or rock during the night. Some damselfish feed on plankton which they catch by hovering in groups over coral heads in the reef. Others though are herbivores feeding on algae on the coral and are known for being aggressive and territorial. Prior to spawning, male damselfish establish a territory, clean the spawning surface which could be a rocky ledge or coral surface and then try to attract females by excited swimming movements, and even by clicking sounds in certain species. Eggs are laid cichlid style where the female lays a row of the eggs which is then fertilised by the male. When egg laying is complete the female departs and all the egg care is done by the male. The eggs take 3 - 7 days to develop into the free-living larval stage joining the pelagic zooplankton in the ocean. Of the thousands of eggs laid by one female, just one or two might survive to become adults on another coral reef far distant from where they were born.
In the wild, damsel fish have a wide distribution in the tropical and sub-tropical coral reefs around the world, particularly in the Indo-Pacific areas. There are over 200 species of damselfish all of which are active during the day and sleep in holes in the coral or rock during the night. Some damselfish feed on plankton which they catch by hovering in groups over coral heads in the reef. Others though are herbivores feeding on algae on the coral and are known for being aggressive and territorial. Prior to spawning, male damselfish establish a territory, clean the spawning surface which could be a rocky ledge or coral surface and then try to attract females by excited swimming movements, and even by clicking sounds in certain species. Eggs are laid cichlid style where the female lays a row of the eggs which is then fertilised by the male. When egg laying is complete the female departs and all the egg care is done by the male. The eggs take 3 - 7 days to develop into the free-living larval stage joining the pelagic zooplankton in the ocean. Of the thousands of eggs laid by one female, just one or two might survive to become adults on another coral reef far distant from where they were born.
The Blue Damselfish, Chrysiptera cyanea (Quoy & Gaimard 1825), is also known as the Blue Devil Damselfish, Electric Blue Damsel or Orangetail Blue Damselfish. The female is all blue, but the male develops an orange tail. The Blue Damselfish, which can reach a size of 6.5 cm in length, are a popular choice for the aquarium because they are colourful, very active, hardy and can live for several years. In the Patels’ aquarium this species permitted the successful establishment of the biological filtration system in the aquarium. These damselfish settled in well in the aquarium and were not aggressive at all apart from occasionally chasing each other. Lack of aggression to other species probably related to their size of just 4 cm in length, while all the other fish added later were much bigger. Moreover, in the time that the Blue Damselfish have lived in this aquarium, they have not attempted to spawn, even though they have grown and an orange tailed male is present as well as some females. This could possibly be due to the fairly heavy fish load in the aquarium, making the holding of a defined territory for a small fish rather difficult. On the other hand, the pair of clown fish, Amphiprion clarki, which are in the same family Pomacentridae as damselfish have been able to define a territory by virtue of occupying Magnificent Sea Anemone, but have yet to spawn.
There are several other blue coloured damselfish available to the marine aquarist. The Azure Damselfish, Chrysiptera hemicyanea (Weber 1913), also known as the Azure Demoiselle or the Half-blue Damselfish has its front portion of body in bright blue while the posterior portion that includes part of the dorsal fin, anal fin and the caudal fin are yellow. This damselfish only grows to 7 cm. Another damselfish having most of its body in blue with just the caudal penducle and fin being bright yellow is the the Yellowtail Damsel, Chrysiptera parasema. This damselfish, which can grow to 7.5 cm, is also known as the Yellowtail Blue Damselfish or Yellowtail Demoiselle.
Conclusion
The Blue Damselfish, which is probably the best selling marine fish in the UK, is a good fish for beginners as it is hardy and can be relatively long lived when properly looked after. The Blue Damselfish is reef safe nor does it harm invertebrates. Although it can be territorial with other damselfish, this can be kept in check by arranging rockwork to provide multiple hiding places to break up territories and hence decrease aggression. Generally, it should not worry other fish species. All in all, the Blue Damselfish is a good choice for most marine aquarium set-ups not containing large aggressive fish.
The Blue Damselfish, which is probably the best selling marine fish in the UK, is a good fish for beginners as it is hardy and can be relatively long lived when properly looked after. The Blue Damselfish is reef safe nor does it harm invertebrates. Although it can be territorial with other damselfish, this can be kept in check by arranging rockwork to provide multiple hiding places to break up territories and hence decrease aggression. Generally, it should not worry other fish species. All in all, the Blue Damselfish is a good choice for most marine aquarium set-ups not containing large aggressive fish.