hi, i still don't have fish in my aquarium and haven't decided which fish to introduce yet. but one question i have is what happens when fish breed? for example, if i introduce a school of zebra danios, will they breed? lay eggs? how many will survive? will it overcrowd my tank? is it different with livebearers? if other fish are present, will they eat the babies?
thanks
numchuk lansing

The spawning depends on the type of fish.Zebras are egg scatterers,meaning the female will swim by a plant or something similiar and deposit her eggs.The male comes behind her and fertilizes them.Some fish will deposit the eggs gently on slate or the male can wrap around the female to fertilize the eggs.Some use bubblenests some use caves,some dig holes and some use their mouths to hold them.


Some but not all fish are fry eaters but its best to either remove the parents or at least have lots of plants,and a species only tank is best if you want fry.

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http://bountifulbettas.blogspot.com/

"Come to the dark side....we have cookies...and filters/heaters/and water changes!"

In a 16 g planted aquarium, i am worried about overcrowding if the fish did breed. how do I control that, or is it controlled naturally?

IMHO it is controlled naturally with the plants providing a good environment for the fry.

Small "bugs" (infusoria) on the plants provide food in addition to the plants controlling ammonia and carbon dioxide and returning oxygen.

Not to mention the plants provide hiding places for the fry to escape the big fish.


my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

That sounds like it would promote overcrowding, not control it.

If that worries you, and it is good that it does concern you, you could just stick to the fish that typically will only breed in situations that normally wouldn't be seen in a tank, unless someone was intentionally trying to breed a certain fish. For example...Cardinal Tetras need very specific water parameters, dark environment, etc.. in order to breed. I have Cardinals in my tank, but I plan to never give them the environment they need to induce a spawn.

Liverbearers is whole different animal. As the term implies, you'll never see eggs with them and before you know it there are babies in your tank. I would suggest you don't get any of them if you are worried about having fry in your tank.

You never know. I had no intention of breeding my lemon tetras. Did nothing special or different...today, I noticed several fry in the tank. If they survive and grow, when they get big enough, I have a spare tank I'll be able to put them in. Eventually, I should be able to sell them to a small local fish store.

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20 gallon long:Amazon Swords, Ruffle Swords, Red Flame Swords, Fanwort, Wisteria,8 Lemon tetras,
6 otos, 11 Amano shrimp, 3 mystery snails, 3 Bolivian Rams, 3 black skirt tetra and 2-3 lemon tetra fry
10 gallon: 30 lemon tetra fry, give or take...1 gallon Anubias, Fish: 1 betta

If you are worried about overcrowding avoid Liverbearers like guppies. THe fry are born reletivel large and mobile and even in a tank with adults enough can survive to become overcrowded.

Most egg egg scatterers like danios and tetras are unlikely to bread in your aquarium unless you have a special setup for it. Most of the eggs will get eaten and if any fry were to hatch they would probably be eaten before you ever saw them. Of course there are exceptions like scooterlady (who must be doing something right for her lemon tetras) but even then you are unlikely to get more than the odd survivor so overcrowding of your tank shouldn't be a problem.