50 gallon tank care

Question
I have recently purchased a 50 gallon tank for a friend who loves betta, oscars, and jack dempsey fish. He currently has a female betta. He wants a big tank--But even though I got him one--I am unsure of his ability to care for the tank- and most importantly the fish that will go into the tank!! So since I am not a "fish" person I thought that you could be of great help to me,him, and the fish! Please let me know the most important things to remember in caring for a large tank of these particular type fish. thank-you so much!

Answer
Hi Shelley,
 That is very generous and thoughtful of you.  

 The key to maintaining any fish tank is to do regular water changes. I advise changing 20% of the water once a week, every week.  Even if one has a great filter, this is a necessary thing to keep the fish happy and healthy.  

 There is a potential problem with the mix of fish that you mention.  Oscars and Jack Dempseys are both wonderful, interesting fish, but they are also at the top of the food chain. Basically, they eat fish like bettas.  They don't eat bettas per se, because a betta comes from South East Asia and oscars are South American while Jack Dempseys come from Southern Mexico.  The bottom line is that your friend can't put a betta in a tank with an oscar and expect the betta to last very long.  

  In fact, you really can't put much in with an oscar and expect it to last very long.  It's not that oscars are mean, they just do what they do and they do it very well.  Now, in return, while you can't have a community tank with an oscar in it, many people find having an oscar by itself is a truly remarkable thing.  Oscars are highly intelligent and easily recognize individual people.  An oscar doesn't need (or want) a friend in the tank -- they get all the attention they need from people outside the tank. On top of that, an oscar can live well into its teens and people who keep oscars get VERY attached to them and vice versa.  

  The Jack Dempsey is a little (but only slightly) less of a predator than the oscar but still you couldn't put a betta in with it.  You could put other large Central American cichlids in with a Jack Dempsey and they would likely do fine.  

  The betta would be perfectly happy in a 20 gallon tank in which you could have a male and female betta (or even a few females -- don't put more than one male in the tank) provided that there were plants and things like that to break up the space and provide hiding spaces for the females. Male bettas can be incredibly persistent in their courtship and the females need a place to go and take a break every now and then.

  I hope that this helps.

-- Ron
  rcoleman@cichlidresearch.com
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