annmg,
No - it is not as good as 'fresh' tuna, but it is still good for you nonetheless.
When getting canned tuna, get Albacore tuna packed in water - it will have the highest Omega-3 levels. The problem with getting it packed in oil is that the omega-3 mixes with the oil and is partly lost when you drain off the oil. Fresh tuna is higher in Omega-3s than the canned variety. The reason being most canned tuna is cooked twice during processing and some Omega-3s are lost.
"Light tuna" is a bit lower in Omega-3 than Albacore.
One warning about tuna - the FDA recommends that "pregnant and nursing women, women of childbearing age and children limit their consumption of canned albacore tuna and tuna steaks to no more than 6 ounces per week and light tuna to no more than 12 ounces per week". This is due to the mercury content in tuna.
Salmon is also very high in Omega-3s - you can get that canned also. Pacific Salmon is significantly lower in mercury than Albacore also.
I'd say eat the tuna and salmon in place of red meat - on a salad is great. If you want to go with the light-tuna (lower in mercury) you can make up for the Omega-3 with a fish oil capsule.
HubbleRules