An interesting article I found about water changes:
Seems to be a lot of interest in water changes - a how much, how often etc. I change 30% of the water once a week because I dont have time. I would like to change it twice, but I've gotta eat! Now heres the result from a little experiment we did back at the aquaculture center at Uni of Tas in 1992. We we looking at differing growth rates compared to water quality. The fish we used were discus and dwarf gouramis. The filtration in one group of tanks was a sponge filter, another group had a trickle system, one had an 'all singing and dancing system' consisting of trickle, nitratereductor,sulphur,carbonate, calcium reactors and another which I cant remember. The last system was getting a 50% water change each day. The results were interesting. The fish with the highest growth rates were from the tanks with the all-singing -and-dancing filters, next was the water change tank, followed by the sponge then trickle (I think). The lecturers do this experiment to show the importance of filtration. Now we wondered why this could be so. Upon examination of the fish (histo-toxicological), it was found that the fish with the highest growth rates given the same food had less blood cortisol levels. When a fish gets stressed, it produces cortisol which lowers the immune system, reduces resistance to infections/pathogens and ultimately inhibits successful spawning in some cases. The reason behind the higher stress levels in the water changed tanks WAS the water changing (physically disturbing them) or buildups of toxic metabolites (remember that biological filtration only removes nitrogen bases metabolites and converts it to nitrate). Also these fish were not used to being disturbed with water changes like mine are, but still - food for thought. Wild stuff, like Heckels wont tolerate any disturbances during spawing season, or they just wont breed!
So the results are interesting. I just thought I'de share this with you. Also, so only way I've bred Heckels out of the pond was by using a stable system with all the bell and wistles in the filtration end. Large water volume (as we fish disease guys say - 'dilution is the solution to polution!')
Someone answered one of the threads in this forum with ' there are too many vaiables with water changes' ie whos right or wrong about frequency of the changes. Dead right - a large tank with low biostock density needs less changes. More intensive systems EG fry growout are gonna need more changes. It really comes down to stocking density. If I walk into my fish shed and see some discus looking a bit dark or not eating with enough vigour or flighty, then I give them a water change. As most of you will know, each of your discus have their own personalitys and traits. I know each of my 20 or so adult brooders by name and personality and I know when somethings not right. Thats when I do my changes.
If anyone wants to try out some of these hi tech filtration systems, have a look at them on Proteus' Non Authorised Commercial Entity site. They can be expensive but are well worth it (and yes - you'll still have to do water changes, but not as often) Food for thought
- Hope some of you guy's find this interesting...
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