Hi to you,
I would not expect a strong or fishy odour from a bitch that was having a normal heat discharge. There is possibility that the heat discharge is unhealthy, maybe heavier and that it is giving off the fishy odour. Even if your dog is not showing any other signs of ill health I would still get her checked over by your vet, in case of a medical condition such as an infection. Another possibility is a problem of full anal glands which might cause the odour even though your dog shows no sign of irritation to her rear. Not every dog shows that classic sign even when the glands need emptying. Get a vet to check this problem just in case your dog is unwell.
Cathy Wickenden BVet Med MRCVS
Barton Lodge Veterinary Centre
1 Midland Road, Hemel Hempstead, Hertfordshire, HP2 5BH
Tel: 01442 216048 24 hours
[
www.bartonlodgevets.co.uk]