how to determine the gender of a goldfish,black moor,black molly and breeding heart?

Goldfish such as black moors are cold water fish and should never be kept with tropicals such as mollies and bleeding heart tetras. So, no, it is not alright to keep these fish in the same tank.

You didn't attach the video.

The black moor and goldfish shouldn't be kept with the others - these are both varietes of goldfish and are coldwater (best in temperatures 65-72oF), the rest are tropicals (temps of 76-85oF).

The molly will be easiest for determining the gender - all you need to do is to look at the anal fin (the bottom one closest to the tail). In a feamle, this looks like the other fins, but in a male, it's thin and pointed - compare the fin in this set of platies - male: http://fish.orbust.net/images/male2.jpg female: http://fish.orbust.net/images/female.jpg The molly's fins will be the same shapes.

In goldfish, you can only tell when the fish is at least a year old, and they're in spawning condition. This link will show you in photos what to look for: http://www.bristol-aquarists.org.uk/goldfish/info/...

In a bleeding heart tetra, the female will be plumper, and a male has a larger dorsal (top) fin.

Alright well first off you DO NOT want a Molly in with the goldfish. Bad idea. Tropicals can't mix with goldfish, they will kill each other. And even if they dont, they arent going to be very happy. Also, if you chose to have more than one fish in a tank, be sure to have at least 10+ gallons for each one. Golfish and Moor's can get pretty big. As for sexing your fish, they have to be a least year old to be sure. Check out the attached link; I find it useful :] I hope this helps, and good luck!

first it's bleeding heart.the black molly has different need(water/salt) to goldfish so i personally would not think it wise to house them together.

GOLDFISH;

Natural habitat:stagnant,slow flowing water.(china)

Size up to 35cm

Maintanance:400-600L is good for 6-8 fish

PH:around 7.0

Temperature:5-25c

Water change:every fortnight

FOOD:omnivours

Reproduction:female lays up to 1000eggs

Life expectancy:20yrs.

the sexual differences are best spotted when they're mature.Mature females are slightly plumper and a so called spawning rash ,which displays as small white spots on gills&gill covers during mating.

TEMP:2-25c.17-21c is ideal.12-24c for veil tail.

oxygen rich,well planted aquarium.

Food:omnivores.Golfish preparations fine/vegetation great.

BLACK MOLLY:

Natural habitat:estuaries&rivers.(mexico,us,south america)

Size:6-7cm,female up to 9cm

Sexual differences:Male has anal fin ,gonopodium(boy bit)

female rounder,fan shaped anal fin

Behaviour:calm,peacfull

Maitanance:Well planted,minimum volume of 100L for two males to 6-7 females.

PH;higher than 7.5

Water hardness:greater than 20dH.with SEA SALT added.

Temperature:26-28c

Change water 15% per week

Food:greenery should always be available,some pellets+small live/frozen prey

Reproduction:Viviparous(specifically ovovviviparous)Birth live young

Life expectancy:2yrs

good with others with same water requirments.

BLEEDING HEART TETRA:

Origin:upper amazon basin(peru,colombia)

Natural habitat:river banks with entangled roots.

Size:6-7cm

Sexual Differences:The male has longer dorsal&anal fins&is larger than female

Behaviour:likes to live in shoals

Maintanance:A 240Ltank is suitable for a shoal of about a dozen.

Ph:6.0-6.8

Water hardness:3-15dH

Temperature:23-26c

Change water:every two weeks

Food water:carnivorous

Reproduction:pair spawn in open water

Life expectancy:3yrs

hope they help you out.Sorry about the celcius&tank sixes are just examples to judge off.

Long tail goldfish are males. Females. tend to be shorter and its butt will be bulging out even more.