Policing The Fish

by Janine Elliot

A while back I was digging a hole in my garden of remembrance for my latest victim. I grabbed reluctantly a rigid 7 inch Oscar and fitted him snugly in the hole I had just dug before covering it over with earth, thinking of the lovely flowers that might grow on top. Whose fault was it that I was in this predicament? Now, before you all reach to your phones and send out a call to the RSPCA please don’t miss understand me, I didn’t intentionally kill it. I just knew that on the Friday it would probably be dead by the weekend. However, if my judgement was so good, then why did it die?

Well, most if not all of us will know that you mix fish with Oscars at your peril, just as you police your Malawi’s or wherever they are from, with due regard. But before we start to keep fish, certainly Oscars, we need to know what is going on in their minds, what is second nature to them. And, indeed, just how far related are Cichlids, particularly, from Humans?

Cichlisoma, like us, need their own space, just as we don’t like it if we get it infiltrated by someone else. .When the Argentineans invaded the Falklands we weren’t going to sit back and just let it happen (I once had a fish I called MT after Margaret Thatcher. You can guess it wasn’t a guppy). So how unreasonable is it for us to be upset when a Cichlid does the same? What we really need to do is understand the minds of the fish and ensure that we can police their 48”x18”x15” world.
Compared with the Lake Malawi (about the size of the North Sea) they have it really bad in our little glass tanks. However, there is conflicting views that less space is better for them in terms of policing. More on that later. Generally we keep Cichlids for breeding purposes, but whether we do or not, like most Human males this is the first thing on their tiny minds. So in terms of keeping Cichlids, “size” of tank and “breeding” are closely related. A few technical terms which might help:

Maternal Mouthbrooder - Male holds territory to demonstate strength and fitness to pass on genes. Female is usually not territorial.

Biparental mouthbrooder/substrate spawning pairs - Pair holds territory in order that there is a safe area in which to live.

Harem polygeny - This is the most interesting lot to watch; what you have is a male who has relationships with lots of women, so he has his own “super erritory” to keep watch on and within this the women have their own individual territory to watch, and woe betide any woman who enters someone else’s area. I have even seen when one woman was fed up looking after her babies so she passed them on to another mother to have. Quite entertaining.

Even before the male has found a partner he will find his own territory so that he will be ready for that occasion when a woman will happen to be passing by. Clever forward planning, me thinks. Discussion on breeding and brooding techniques some other time. I just want to look at the psychology of the fish within the tanks. So we see that the male generally gets to hold territory before a woman. It is also seen that only the strongest males will be likely to attract the females (isn’t the similarity with humans interesting). This has a secondary factor in that only the stronger fish will produce healthy babies. By attempting to control the breeding habits of our fish we can cause more problems in producing weaker fish, and this is especially evident when we continually breed the same stock. So now perhaps the subject of having large numbers of the fish in one tank can seem preferential. Also, if we do decide to keep only a pair of fish in a tank, the male’s need to defend his territory ceases and so he may well turn on the wife. By adding another fish or even just seeing another fish in a tank at the side might prevent this. Also, the female might get killed if she doesn’t respond to his sexual advances, whether during the initial courtship or after having babies! And finally, “marriage for life” is not the norm in fishes, contrary to what some people might say.

So, what exactly can we do to solve this territory phenomenon? Whilst most people think that designated areas within a tank is the best method, others think that by not giving fish their own territory fish will then not feel territorial and have to live together in harmony together. But then without anywhere to hide the fish being attacked has no chance of survival. By crowding a fish tank makes it harder for a specific cichlid to feel he is “boss”, and can ensure a better policing of the aquarium.

If you do wish to set up territorial areas it is vital that they are not overlapping as shown in the picture (males are shown as purple, females as blue). If there is an overlap there are likely to be arguments just as humans have over whether their fence borders a neighbours garden. In a crowded fish tank it is easier just to let the fish decide where to live, and actually, they usually do anyway.

So what can we do to keep our fish in order, other than carefully plan out the tank before putting any fish inside? I have put in my own form of “police fish” into my tanks to keep peace and order on a number of occasions. It seems to work really well, though it frightens them a bit to start with. Costing £5 from The Gadget Shop it has been a bit of fun as well as a cheap fish-security measure! As you can see by the photo, my battery operated toy soon made friends with even my Oscar!

Finally, I wanted to make a few suggestions as to keeping larger cichlids in a tank. Firstly, when a Cichlid wants to make its own territory known to everyone else it marks the spot by totally rearranging the furniture. This includes the large rocks or slate you have meticulously placed inside the tank. And, don’t even attempt under-gravel filtration. The fish will remove all the stones in his area and as well as looking a mess this will ruin the affect of the filter. With baby fry in a tank an under-gravel filter is also not advisable.

I’ll leave you with these thoughts. Does a fish have the right to mark out its own territory? And when a Cichlid has marked it off, how much right does another fish have to infiltrate the area, and is it unreasonable for it to be upset at the least? After all, don’t human beings think like fish? Perhaps we should be saying that fish aren’t aggressive as they are own looking after their own interests, or perhaps fish are not much different to human beings after all. Now, I wonder if my Oscar would like me to put a television set in the corner of the tank…...