Arowana Eating Habits

Unlike most other fishes, arowanas are able to withstand a long period of fasting. A growing arowana should be eager to accept food but it can also go on periods of fast, some of the reasons can be listed below, based on hobbyists' experience. The discussion is in this thread.

Reasons Arowanas go on a fast:

1. Physiological

1.1 Poor water parameters. The presence of ammonia and nitrite in the tank is an indication that the filtration is inadequate, one can do water tests (Sera ammonia and nitrite tests are available in most lfs) to ascertain whether there is ammonia and/or nitrite in the tank and correct the situation by increasing filtration capacity. Too high or too low a ph also impacts an aro's appetite. Generally, a ph between 6 to 7 is acceptable to most aros, anything outside this range is considered exceptional, some aros accept it, others may not, it's just a matter of getting used to the condition - but it is ideal to keep it in the recommended range.
Too high a gh could also impact appetite as aros are more comfortable in soft water, and there are reports of high gh causing chipped scales. High gh can come about when there is too much coral chip/oyster shells in the filters. IMO one need not go to the extent of using RO water to bring down the water hardness level, but just keeping the tank with minimum or no coral chip would be ideal for the long term.

Regular water change (once a week) is highly recommended to speed up growth and increase appetite. If bioload is high in the tank (eg in community tank with several fishes), twice a week would be better.

1.2 Disease
The diseases that can afflict all fishes, such as velvet, ick, HITH/lateral line erosion, etc.
Aros are more often afflicted by anchor worm infestation, bacteria infection arising from exposed wounds (caused by jumping, tankmates, etc), viral infection (characterised by lumps on the fish). There are cures for anchor worm and bacteria infection, by the use of medication sold in lfs or obtainable from a vet. There is no cure for viral infection but usually it is harmless to the fish, except for the unsightliness (some books recommend medication with acriflavine in it, and this has been known to be successful in some cases)

As with all diseases, early treatment is necessary before complications set in once the fish's immunity' gets lower.

1.3 Inadequate nutrition

Vitamin supplementation is recommended to ensure aros have adequate nutrition.

2. Psychological

2.1 Stress caused by tankmates

Aggressive tankmates or large looking fishes sharing the same tank as the arowana could affect the latter's appetite. Some aros could be spooked easily by their presence eg of rays.
Remove the tankmates that could cause stress to your aro.
There are reports that the right tankmate could help the aro to increase it's appetite. Eg greedy tankmates could spur an aro into grabbing as much food as possible.

2.2 Stress caused by change in environment

Tanning could also affect appetite, it is advisable to gradually increase the hours of tanning in the beginning so as to minimise the change to the arowana. It has also been reported by hobbyists that warmer water could increase an aro's appetite due to the raised metabolic rate. An underwater tanning light would raise the tank temperature, and a heater as well, but usually heaters are not necessary for healthy arowanas, it could be experimented with if an aro has poor appetite.

2.3 Picky - prefers one food over another. Most aros like crickets and centipedes, but feeding these could also cause the aro to ignore other food. A good mix is recommended but for some aros, it is best to avoid offering these food totally as they are difficult to wean off such food. Super worm is also another food that is readily accepted by aros, it is a good food to attain growth, but however, too much SW could lead to fat deposits in the aro, and is also known to cause dropped eye in some aros. DE does not only come about from feeding SW, it is a condition that could be caused by a combination of several factors including poor diet, eg excessive tanning, fatty diet, genetic dispostion, etc.


This thread will be updated upon further discoveries and insight from hobbyists.