A second vessel (Florentia) was ordered on 26 March 1846 but after her keel was laid at Pembroke Dockyard, her construction was suspended on 6 October 1846 then cancelled three years later, on 22 May 1849.

In 1850 when commissioned, the armament was changed to fourteen 32 pounder 25 cwt 6-foot MLSB solid shot guns on broadside trucks.

[2] During her full power steam trials her engine generated 1,002 indicated horsepower (IHP) for a speed of 10.25 knots.

Since both ships had the same lines and steam engines developing almost identical power, the results confirmed the superiority of screw propulsion over the paddle-wheel once and for all.

[2] She was commissioned at Portsmouth on the 9th of July 1850 under Commander Leopold G. Heath, RN for service on the West Coast of Africa.

On 28 March 1860, during the First Taranaki War, a party of approximately 60 marines and bluejackets under the command of Captain Peter Cracroft landed at Waireka as reinforcements in the engagement that was taking place there.

After reaching the Omata stockade near dusk, they proceeded to storm the by now lightly defended Kaipopo Pā.

Coxwain William Odgers broke through the palisades and pulled down the Māori ensigns flying there, and received the first Victoria Cross of the New Zealand wars as a result.

[7] Later in 1860 the detachment of Marines was stationed as a garrison at Fort Niger, a hill overlooking the New Plymouth suburb of East End.

[3] On 3 February 1865 she was commissioned under Captain John C. Byng, RN for service on the North America and West Indies Station.

[3] On 3 March 1865, HMS Niger ran aground in the River Thames at Greenhithe.