Why am I seeing little black fleas?
Little black fleas are the immature stage of the flea.
Seeing a large number of little black fleas on your pets generally means one of two things. If you are not using an effective flea control it means that very recently your pet was exposed to an environment with flea stages just waiting for a pet to 'hitch' a ride on. Since you are not using an effective flea control you can be sure that within a day or so, your pet will be crawling with adult fleas which are larger and brown rather than black in color. You will also start seeing the flea dirt or droppings which is mainly dried blood. The bad news is that within about 48 hours these fleas will start to lay eggs in your pets surroundings - you need to start using an effective flea control product immediately.
If you are using an effective flea control, then seeing a high percentage of little black fleas rather than the larger brownish fleas is a good sign. It means your flea control product is actually killing the majority of fleas before they have the chance to mature and start reproducing. It normally takes a minimum of 24 hours on the pet before a flea will grow to a mature size. Generally, if greater than 70% of fleas present on an animal are present as small black immature fleas then the product you are using is working well - you just may need to work out, where the environmental source of extra fleas is coming from. Remember, if you are mainly seeing immature fleas, you can be pretty sure the fleas that you are seeing today will be gone tomorrow, and that any immature fleas you find tomorrow will have arrived very recently.
Generally if you have only recently started using an effective flea control product, you will need to wait some weeks (up to 6-8) before all of the flea stages in your pets environments have passed from larvae, through pupae and finally to the immature flea which first jumps onto your pet - so you may be seeing the pesky little black immature fleas for a few weeks yet.