This is part of the article originally written by Bryan Jones and was in the Aquarium World Nov '99...
Rummynoses are not difficult to keep but they are fast movers and have a high metabolism rate. They prosper in good quality water with a maximum saturated oxygen content. An OPP (oxygen replacement percentage) meter or similar is of assistance, particularly when tank numbers are high or when shipping them out in plastic bags. Regular water changes are of particular importance in growing a large school of these fish.
Breeding a Few Hundred
Get a breeding stock of 12-20 healthy young fish to ensure you obtain both sexes. Go for the bleheri species which should show the bright red head (although I suggest all rummy-nose imported into NZ are this species). A tank of 60 x 30 x 30cm should house the breeders. It should not need to have substrate as it may harden the water. A few plants in pots or growing on sunken driftwood can be added for decoration purposes.
Make sure the water is matured, soft, well filtered and aerated. Add some peat to the filter or hang a stocking filled with peat in the tank to acidify and soften the water. Rummynoses are hungry feeders and grow fast.
They will take most foods but use live foods and frozen bloodworms to fatten up the females with roe. They seem to relish the frozen beef heart formula that I make up for my discus.
When the females are fat with eggs, which will be easily observed, the sexes should be separated a couple of weeks before spawning attempts. Mature males have the Characin hook at the front of the anal fin which frequently catches on the net when catching fish.
During the week before placing the adults in a breeding tank, provide daphnia (if available) each day as this live food seems to bring breeders into top condition for releasing eggs.
Rainwater should have previously been collected and stored in a large container, such as a barrel. A couple of stockings filled with peat should be soaked in the water for some weeks. pH should be around 6.0 - 6.5 and the water soft - below 50 micro siemens. The rainwater in my storage barrel is sometimes down to 20ms which is very soft. Water can be acidified by adding phosphoric acid (H3P04) but it is more natural to use peat concentrate as it will also impede bacterial growth.
I usually set up three 45 x 23 x 23cm breeding tanks which have been well sterilised with potassium permanganate solution, ICMNO4, including airstone, egg catching grill and cover glass. Add the soft water to a depth of 12cm, warm it to 24°C and provide light aeration. I do not believe the temperature is that critical as I have bred a number of Characins around the year in a fish room that is cooler in winter and hotter in summer. Water in the breeding tanks, depending on high or low position on shelves, can range from 22° - 28°C.
The stainless steel grills I use, to protect the eggs from hungry parents, have a mesh of 3mm. Make sure they are flat and fit tightly around the tank floor as breeders can sometimes get under the edges and die. Egg crate (with 1cm squares), which is used to diffuse light from fluorescent units, can be cut to the same size and also used with equal success as an egg saver.
Mask the tank with black polythene cut to size leaving a cut out window along the top half of the front glass. All my breeding tanks have been painted black on the bottom outside to reduce light and make the breeders feel secure. For rummy-nose I add two untangled green plastic mops, as a spawning medium, to make surrounds more natural. Make sure the mops are well untangled so as not to noose fish in small loops. Beware of using nylon mops as I have had male fish well caught up in them by their anal hook.
Carefully catch 2 females and 3 males and release them into the breeding tank in the morning. Rummynose breed at night similar to cardinal tetras - usually on the second night after introduction. A swirl of the water with a plastic spoon with a torch light behind will usually reveal a number of clear eggs.
Take out the fish and mesh grill, add 5 drops of 5% Methylene Blue and cover the tank with cardboard or similar to exclude light.
Keep light aeration going to make sure the water is well oxygenated and scum does not develop over the water surface.
Five days later, remove the covers and check for fry. These should be seen scooting around on the bottom. Depending on water temperature, the fry will be ready for a very small amount of newly hatched brine shrimp in the afternoon of day 5, or morning of day 6. Don't feed anything if the fry are just hopping about and still show signs of a yolk sac. They should be swimming just over the tank bottom. This is where a torch or light from behind is needed to see exactly what is going on. I have a magnifying glass for assistance as well.
After feeding a small amount of brine shrimp, check 1 hour later for pink tummies. If this is observed, feed very small amounts 3x per day or at least morning and late afternoon. I do not use, or recommend, infusoria as the fry can take brine shrimp from day 1 but micro worms can be used as a supplementary food.
The first few days are the critical time for success or failure in obtaining results. Do not overfeed, and check regularly for surplus and dead brine shrimp some hours after feeding.
Each day add a little matured soft water at the right temperature and include a small sponge type filter after the fry have been feeding for 3 days. This will inhibit the build-up of bacteria and help to keep the water in top condition. The water level should now be up to 20cm deep.
If fed and housed correctly, and top water quality maintained, rummy-nose fry are fast growers and should reach adult in size in 6 - 9 months.
