Brackish Water Fishes IV with pictures - Aqualand Pets Plus
Photo provided by Flickr
The flowing through is a classic river estuary. The town of a few miles west of London marks the boundary between the tidal and non-tidal parts of the Thames, although it is still considered a freshwater river about as far east as insofar as the average salinity is very low and the fish fauna consists predominantly of freshwater species such as , , , , and . The becomes brackish between Battersea and , and the diversity of freshwater fish species present is smaller, primarily roach and dace; marine species such as , , , and become much more common. Further east, the salinity increases and the freshwater fish species are completely replaced by euryhaline marine ones, until the river reaches Gravesend, at which point conditions become fully marine and the fish fauna resembles that of the adjacent and includes both euryhaline and marine species. A similar pattern of replacement can be observed with the aquatic plants and invertebrates living in the river.
Photo provided by Flickr Marine species will only combine well withbrackish water species that enjoy half to full strength seawater. Thisincludes most of the big brackish water species such as scats, monos,archers, moray eels, and sleeper gobies. Salt-tolerant freshwater fishon the other hand, including cichlids such as kribensis and orangechromides, glassfish, guppies, spiny eels, knight and bumblebee gobies,and figure-eight puffers, cannot be kept at high salinities and cannotbe mixed with marine species.
Photo provided by Flickr
Photo provided by Flickr
Photo provided by Flickr
Brackish water fish need water that has more salinity than freshwater but less than sea water. The exact salinity level of the brackish water depends on the location. Obviously you will want to keep the fish listed on this page in species or biotope specific aquariums due to their brackish water requirements.Top of my list of marine species for thebrackish water aquarium are two Asian pufferfish, the dog faced puffer,, and the milk spotted puffer, . Both are relatively peaceful (by pufferfish standards atleast), hardy, and in the case of the dog faced puffer, quite commonlytraded and inexpensive. While I was a student at Aberdeen University, Iused to take trips to neighbouring towns and cities to find stock forthe two 200-gallon aquaria I helped to maintain in the Department ofZoology. On one particular trip to a store in Dundee I came across atank containing a bunch of attractively patterned pufferfish. They werebeing kept in the slightly brackish water along with some more familiarfish, but what immediately caught my attention about them was thatunlike the usual fresh and brackish water puffers, these fish were notsome variation on the theme of 'green and spotted', but brown,with a creamy white underbelly and a nice pattern of grey stripes andspots across the flanks.While this event signals the end of my fishingexpedition on this particular day, it has made me think about thepuffers, their environment, and the other fishes swimming about thereef with them. For a start, the salinity here fluctuates with thetide, from about half to full strength sea water. The vegetationconsists of a mixture of mangroves and salt tolerant marsh species suchas various sedges and reeds. Some of the fish species are ones youwould normally associate with freshwater habitats such as garpike, spp. Then there are those species that we morefrequently associate with brackish water habitats, like mullets, snook,and ariid catfish, , , and being especially commonhere. Finally, there are the fish that normally inhabit marineconditions but will enter brackish waters if the mood takes them. Thepufferfish are just one example of these fish, in this case to takeadvantage of the rich shellfish hunting grounds that exist on oysterbeds. Another species that does much the same thing are sauries, largemarine versions of the more familiar halfbeaks, attracted here by theschools of small fish, in particular juvenile marine species, that lookfor safety among the rocks and mangrove roots. Various species ofsnapper, jack, and porgy hunt here as well, and in turn provide goodsport for anglers too.Damselfish are primarily marine in occurrence,but a few do venture into brackish, even fresh, waters. One of the mostcommonly found in shallow coastal waters other than coral reefs is thesergeant major, , and provided the specificgravity is kept above 1.015, these fish will settle into high salinitybrackish water aquaria quite well. In captivity it is often ratherterritorial towards other damsels, and so is best kept alone, but itdoes have character and readily becomes tame enough to be hand fed. Assuch, it makes a great personality fish to combine with active,schooling species like monos.