9: requirements and enrichment

by Paul Veenvliet
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9: requirements and enrichment

Post by illustrator » Tue Nov 25, 2008 9:37 am

In this subject I intend to discuss some ways to enable convict cichlids to show parts of their natural behaviour, but I feel that I should start with a general basis. So first: what are the minimum-requirements for the keeping of convict cichlids? Many internet sites list these as well, but don't aree with all. So here's my version:
Last edited by illustrator on Thu Feb 05, 2009 6:08 am, edited 4 times in total.

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11: requirements & enrichment

Post by illustrator » Mon Jan 12, 2009 6:42 am

Some aquarium measurements and other minimum requirements

Minimum aquarium length:
60 cm / 24 in (3-5 young convict cichlids up to 3,5 cm body length)
80 cm / 32 in (adult pair)
120 cm / 47 in (adult pair with dither fish)
150 cm / 60 in (2-3 adult pairs or adult pair combined with other Central American cichlids)

In my opinion aquarium length is far more important than aquarium footprint (= bottom surface). Convict cichlids defend a territory, which is something like a distance from a central territory point. This distance is the same in a narrow and in a broad aquarium. In a long aquarium there are more opportunities to get away from a territory for a submissive fish.

Temperature:
22-26'C / 72-79'F

Water chemistry: not important as long as nitrite/nitrate is low: meaning that tap water is usually suitable as long as 1/3 of the water is changed every 1-2 weeks. Chlorinated water should only be used if it has been standing in a bucket for a night (best with aeration). But: an aquarium filter is necessary for this species!

Shelters: clay flower pots function well, but are rather ugly. A pile of large stones works equally well. Some kind of shelter is necessary in any case.

Bottom cover: a bare glass bottom is not only ugly, it also shows what is underneath the aquarium, which is often a white plate of styropor. Nearly any fish prefers a dark coloured underground. Gravel is OK, sand is better (I'll come back to this).

Aquarium cover: this houses a light and at the same time makes sure that there are no sudden shadows (of owners) from above. Shadows are very stressy because they resemble predators (think about herons).

Background: look through aquariums are wrong: they don't provide quiet corners. Either place the aquarium against a wall or put something on the back of the aquarium. It is not important what, as long as the colour is not very light. Cheap options: paint the backside of the aquarium (on the outside) or buy a decoration poster (which I did). Any of the fancy special aquarium backgrounds is also OK, just costs more.

Food: little bits, 1-2 x per day. Too much food leads to excessively large, fat and overly aggressive fish. I have good results with granulate from JBL, but many brands/types are probably OK.
food.jpg
food.jpg (136.55 KiB) Viewed 4992 times
Daily portion for 28 fish (1 adult convict, 9 young ones, 10 zebrafish, 4 swordtails, 5 Ancistrus). Granulate is eaten in 30 seconds, pleco-tabs (JBL) take a bit longer. Convicts eat both types of food.
Last edited by illustrator on Wed Feb 04, 2009 12:30 pm, edited 4 times in total.

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Re: 12: requirements & enrichment

Post by illustrator » Tue Jan 13, 2009 6:18 am

In nature, animals spend most of their day searching food and avoiding predators. In captivity, animals eat all their food in a few seconds and there are usualy no predators to avoid. Captive animals tend to spend much more time on social interactions (territorium defence, courtship) but they can also develop unnatural »stereotypic« behaviour. One of the challenges for aquarium keepers is to enable fish to carry out much of their natural behaviour, including fouraging behaviour. For this purpose we can include all kinds of »objects« in the aquarium. In zoo-terms, this is called »environmental enrichment«. Practically it means giving fish »something to do«. A simple form is giving a golfball to a large cichlid. This looks unnatural, but many cichlids keep pushing it too and from, and it's better than nothing. For convict cichlids I chose a number of other, more natural looking »objects«.

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Re: 12: requirements & enrichment

Post by illustrator » Tue Jan 13, 2009 6:31 am

Plants

I often read that convict cichlids eat plants and destroy plants. However, my experience is different. Sure, convict cichlids dig, but they do not dig out plants on purpose. Rather, they dig to search food and to make holes as hiding places for their offspring. The solution is simple: put some large pebbles on the plant roots and they can no longer be dug out. Take care that small convict cichlids sometimes dig between large pebbles: some smaller gravel can prevent this. I tried with a variety of plants and none got eaten. Not all were growing well, but this was not because of the fish (limited light was probably the problem). Plants provide hiding place sand convict cichlids often search for food between plant leafs. They also push lant leafs away to »look under«, but this does not damage the plants.

I prefer real plants over artificial because plastic is tough and sharp, and I am afraid that a fleeing fish migh damage itself between dense plastic plants. Also, I just like real plants … 8)

Untill now I tried with the following plants: Riccia fluitans, Vesicularia dubyana, Microsorium pteropus, Ceratophyllum demersum, Hydrocotyle leucocephala, Vallisneria spiralis, Echinodorus cordifolia, Cryptocoryne balansae, C. walkeri, C. wendtii, Pistia stratiotes.
fishplant.jpg
Young convict cichlid between Cryptocoryne wendtii.


Note: I am currently trying with Hygrophila polysperma, which is more delicate and looks more like something that a fish might eat. To be continued ...
Edit (29 january 2009): the convict cichlids bite out some of the growing tips of this plant species. Since most of my cichlids are still small, I expect that Hygrophila will be quite destroyed by adult convicts.
Last edited by illustrator on Thu Jan 29, 2009 3:38 am, edited 4 times in total.

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Re: 12: requirements & enrichment

Post by illustrator » Tue Jan 13, 2009 8:22 am

Leafs

Leafs from trees cover parts of the bottom of most streams, worldwide. Invertebrates hide between these leafs and convict cichlids habitually flip over leafs to look for these invertebrates. Convict cichlids also do this in the aquarium, only much less frequently because they hardly ever find something under the leafs. I think that it is still good to provide leafs, even if cichlids flip them only occasionally.

I have no clue which tree species grow in Central America, but I found that local European leafs are OK for the purpose. I use leafs from beech trees, which is a common tree in my area. These leafs decompose slowly over the cause of several months. I collect a handful of leafs in the forest and put these straight into the aquarium: no cooking/disinfecting or whatever. The leafs float for a day and then sink down.
beech.jpg
Beech leafs, still on the tree.
turning.jpg
Convict cichlid looking underneath a beech leaf.
Last edited by illustrator on Thu Feb 05, 2009 5:34 am, edited 2 times in total.

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Re: 12: requirements & enrichment

Post by Bas Pels » Fri Jan 16, 2009 5:18 am

illustrator wrote: Minimum aquarium length:
60 cm / 24 in (3-5 young convict cichlids up to 3,5 cm body length)
80 cm / 32 in (adult pair)
120 cm / 47 in (adult pair with dither fish)
150 cm / 60 in (2-3 adult pairs or adult pair combined with other Central American cichlids)

In my opinion aquarium length is far more important than aquarium footprint (= bottom surface). Convict cichlids defend a territory, which is something like a distance from a central territory point. This distance is the same in a narrow and in a broad aquarium. In a long aquarium there are more opportunities to get away from a territory for a submissive fish.
Obviously, this is only true in case of narrow tanks

Wheter the tank is 30 cm from front to back or 40 does not matter, and in most cases 50 cm is still the same

However I keep a group in a 400 * 100 cm footprinted tank, and 30 cm from the nest does mean there is still a lott of room to go further to the back

Getting further to the back, fishes encounter more cover, and perhaps this explains why many fishes in this tank have teritories which are longer (parallel to the front window) than deep (right angles to this window).

In this tank the fish thrive, and I had to add Petenia to keep numbers acceptable (adults are not eaten, only fry)

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Re: 11: requirements & enrichment

Post by illustrator » Mon Feb 02, 2009 4:17 am

Feeding snails is another way of giving cichlids something to do. Snails are part of convict cichlids diet, but convict cichlids are not specialised snail-eaters. They have two ways to tackle a snail: the most common is that they try to sneak up to a snail, grab it's body and violently tear it out of it's shell. More rarely they grab a very small snail (up to 2-3 mm shell diameter) and try to crunch it with their pharynchal teeth (it looks like they chew" on the snail).

For the sneaking-technique convict ciclids need an element of surprise, which is why they keep inspecting shells, even if these are empty (which the cichlids obviously don't distinguish very well). In this way, feeding some living snails can keep convict cichlids busy for considerable time. When there is no a living snail around for some time, the cichlids also lose interest in empty shells.
snail.jpg
Convict cichlid "Wilhelm" inspecting an (empty) Helisoma-shell.
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Re: 11: requirements & enrichment

Post by illustrator » Wed Feb 04, 2009 12:25 pm

For many of us aquarium snails are a nuisance. For me, they are fascinating. They are the the creatures that benefit most from our hobby. There’s a set of species that occurs in aquaria worldwide and no matter what we do, we keep getting them with new aquarium plants. Although these species are not closely related to each other, they share some characteristics which enable them to survive in our aquariums. They can reproduce at an early age and have some way to reproduce asexually (either self-ferrtilizing or parthenogeny, depending on the species). In cichlid-aquaria they are less problematic because almost any cichlid will eat any snail, whenever possible. But these snails have co-evolved with fish and they are far from defenseless. For the purpose of making photographs and illustrations I had collected as many species as possible of “nuisance-snails” from the local aquarium shops. Some of these were still multiplying in my aquariums when I got “back to convicts”, and then they were confronted with a serious snail-predator. What happens differed greatly ...
Physa.jpg
Bladder snails (Physa sp.) got eaten in no time.
Helisoma.jpg
Most ramshorn snails (Helisoma sp.) also got eaten, but not all. When one got eaten, some others pull back to their shell and dropped to the ground: apparently wounded ones emit alarm-pheromones and others react to this. The last surviors changed ther behaviour and creep with their shell very tight to the ground: this reduces the chance that a fish can grab the snails’ body. These last ones manage to survive and even reproduce in the presence of convicts, but their numbers stay small.
Melanoides.jpg
Malayan snails (Melanoides sp. ) shifted to nocturnal activity (ever noticed how active they become in a quarantaine-aquarium without fish?) and burry in the ground during day. They have small bodies (offering less grip) and can close their shell with an operculum. However, some of the largest individuals get eaten anyway. BTW: this is an individual from the Austrian stream: also there they survive the company of cichlids.
Nerite.jpg
Nerites just survived. They naturally press their shell against the surface and offer no place to hold them. On the photo is a native European nerite species, but it’s similar for tropical species. Species vary widely in their needs but many cannot reproduce in aquaria or reproduce only in very small numbers. Not really a “nuisance”, but it shows the ultimate cichlid-resistence. (At the same time I am very worried about overexploitation of wild populations for aquarium-purposes ...)
corb.jpg
There's also a single small freshwater mussel (Corbicula sp.) in my aquarium. I don't think that the cichlids even notice that it's alive. I have it for over a year now, which surprises me because I actually bought it with the idea to prove my own statement that freshwater mussels starve in aquariums. Seems I was wrong about this one, but it gives me new worries: Corbicula are highly invasive in some parts of the world, they are in trade and they can obviously survive aquarium conditions for a long time meaning that dumped aquarium mussels can be the start of a new invasion of this species.
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Re: 10: requirements and enrichment

Post by illustrator » Thu Feb 05, 2009 4:54 am

In nature cichlids spend most of their time searching food. Because of this, environmetal enrichment is mostly trying to stimulate food searching behaviour.

One way in which convict cichlids search food is what I like to call "vibrating behaviour" (I don't know if some ethologist have a better term ? ) A vibrating cichlid presses it's belly against the bottom substrate and strongly vibrates it's body, pectoral and tail fins. In the most intensive vibrating posture the other fins are held tightly against the body and the mouth is wide open. As a result of the vibrating, al kinds of particles get flushed from the bottom. After vibrating the cichlid swims slightly backwards and checks for edible things between the particles in the water.

Vibrating is often carried out together with other food searching behaviour. A typical sequence is: -pecking at parts of the sediment- -inspecting a snail/small stone- -pushing the snail/stone over- -vibrating- -checking amongst the now floating particles- . This is carried out in quick succession and can be repeated many times. In my aquarium, convict cichlids "vibrate" most often when there is a strong smell of food present, but visible food particles are mostly eaten. This is some minutes after feeding.

The vibrating behaviour is most effective and most natural on a loose substrate, that is, in some mud or soft particles. If this is lacking, convict cichlids also vibrate on gravel and even on a bare aquarium bottom. Because of hygiene my aquarium is not muddy, but I put sand on most of the bottom as "intermediate substrate". Sand grains get flushed to all sides during the vibrating behaviour and I think that this is kind of a second-best option when mud/soft particles are inconvenient. For this reason I like river sand much beter than gravel or (worse) a bare aquarium bottom.
vib.jpg
Vibrating convict cichlid
vib2.jpg
Even though this photo is technically poor, it shows how sand is flushed up during vibrating.

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Re: 9: requirements and enrichment

Post by illustrator » Mon Mar 02, 2009 1:17 am

The common technique for eating a snail is to sneak up to it, grab it's body with a sucking/biting movement and then tear it out of it's shell with a head shake or by pushing the shell to a stone. This goes quite rough and the sharp edge of the shell often scratches the lips of a convict cichlid in the process. Yesterday I managed to capture these scratches on a photo:
scratches.jpg

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